Poultry rearing on perforated plastic floors and the effect on air quality,
growth performance, and carcass injuries—Experiment 1: Thermal Comfort

Eduardo Alves de Almeida,∗,1 Lilian Francisco Arantes de Souza,∗ Aline Cristina Sant’Anna,†
Raphael Nogueira Bahiense,‡ Marcos Macari,∗ and Renato Luis Furlan∗

∗Department of Morphology and Animal Physiology, São Paulo State University, 14884–900 - Jaboticabal-SP,
Brazil; †Department of Animal Science, São Paulo State University, 14884–900 - Jaboticabal-SP, Brazil; and
‡Department of Animal Science, Federal University of Minas Gerais, 31270-901 Belo Horizonte-MG, Brazil

ABSTRACT The present study investigated the use
of perforated plastic floors in the rearing of male and
female poultry under thermal comfort conditions. The
study was conducted in 2 climate chambers, in one was
conventional poultry litter (wood shavings) and in the
other was a perforated plastic floor. The experimental
design was a completely randomized design with the
factors wood shavings and plastic floor. In each cham-
ber, the animals were divided into 16 experimental pens
(8 with males and 8 with females) with a density of
12 birds/m2. The poultry rearing effect was evaluated
in terms of air quality (% concentration of ammonia
[NH3] and carbon dioxide [CO2]); broiler performance,
e.g., weight gain (kg), feed intake (kg), feed conversion,
carcass yield and parts (%), meat production (kg/m2),
and viability (% of live birds at d 42); scores of hy-
giene and mobility; and injuries in the chest, hocks, and
footpads. Treatments affected air quality, with higher
concentrations of NH3 on d 42 (25 ppm vs. 2 ppm)

and CO2 (1,400 ppm vs. 1,000 ppm) for wood shavings
than for perforated plastic floor, respectively. Males
showed a better performance (weight gain, feed intake
and feed conversion) than females on d 42 in both floor
types (wood shavings and plastic floor). Males reared
on wood shavings showed a higher meet production
(35.992 kg/m2) than females (32.257 kg/m2). On the
plastic floor, males showed a better viability (100%)
than females (94.05%), as well better meet production
for males (38.55 kg·m-2) than females (31.64 kg/m2).
There was no incidence of breast lesions in any of the
studied systems. The birds reared on the plastic floor
had better hygiene scores and lower hock injury rates
than birds reared in the wood shavings chambers. The
results of the present study show that the use of per-
forated plastic floors in chicken farming is an efficient
method, which promotes a better-quality environment,
superior production rates, and reduced incidence of
injuries.

Key words: Plastic floor for broiler, Ammonia concentration, Carcass injury, Poultry litter, Animal Welfare
2017 Poultry Science 96:3155–3162

http://dx.doi.org/10.3382/ps/pex131

INTRODUCTION

According to the United Nations (2013), the world
population is expected to exceed 9.6 billion by 2050,
implying that the production of food is a growing con-
cern. With this in mind, poultry meat is highly val-
ued because it is an animal protein of high quality,
can be produced in a short period at relatively low
cost, and can meet the demand of the population. In
2015, Brazil was the second highest world producer of
poultry meat, with a production of 13.15 million tons
(ABPA, 2016). However, further research and the estab-
lishment of technologies that allow production in higher

C© 2017 Poultry Science Association Inc.
Received July 4, 2016.
Accepted May 8, 2017.
1Corresponding author: eng.eduardoalves@hotmail.com

quantities without harm to animal welfare and that gen-
erate less waste are necessary.

Annually, approximately 7.8 million tons of poultry
litter is produced in Brazil (Benites et al., 2010). The
main materials used as poultry litter are wood shavings,
rice husks, and peanut shells (Miles et al., 2011). Ow-
ing to the high cost and the difficulty in finding poul-
try litter material, producers reuse the same material
for several cycles of breeding in an attempt to reduce
production costs (Lopes et al., 2013). However, accord-
ing to Medeiros et al. (2008), this reuse of poultry litter
over a number of breeding cycles increases the potential
of the undesirable effects of ammonia (NH3) accumula-
tion occurring. Exposure to high concentrations of NH3
causes a decrease in poultry performance (Miles et al.,
2004), affects the immune system (Wei et al., 2015), and
increases susceptibility to disease (Beker et al., 2004).
This exposure can also affect the health of workers who
are in daily contact with this gas (Rylander and Car-
valheiro, 2006).

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3156 ALMEIDA ET AL.

Inadequate management practices that impoverish
poultry litter quality may produce severe impacts on
animal welfare, lower hygiene, and increased carcass in-
jury incidence, thus causing considerable losses in pro-
duction (de Jong et al., 2014). One possible solution
might be to use a perforated plastic floor, similar to
those used for rearing pigs, where the poultry residues
would be constantly removed from inside the installa-
tion, avoiding decomposition and consequently the pro-
duction of NH3. The acquisition cost of poultry litter
material would also be reduced, as would the overall
creation of waste. The use of plastic floors is already a
reality in some branches of poultry production, such as
the breeding of laying hens (Heerkens et al.,2015) and
duck breeding (Karcher et al., 2013; Rice et al., 2014;
Fraley et al., 2013; Xie et al., 2014). However, until now,
few studies have been found in the literature reporting
the effects of using plastic floors in the production of
broilers (Li et al., 2016).

The objective of this study was to evaluate the use
of perforated plastic floors as a replacement for poul-
try litter (wood shavings) for broilers reared under a
thermal comfort environment.

MATERIALS AND METHODS

Facilities, Poultry and Management

The present study was conducted at São Paulo State
University (UNESP) Jaboticabal, Brazil, using broiler
chickens, male and female from the commercial line,
Cobb500 R©, aging from 1 to 42 d (Globo aves, Itirap-
ina, São Paulo, Brazil). The birds were distributed in
2 climate chambers, one with wood shavings as litter
material and the other with a perforated plastic floor
(Big Dutchman, Araraquara, São Paulo, Brazil).

The birds were raised in thermal comfort, following
the recommendations for this particular line described
in the Cobb Breeder Management Guide (Cobb, 2008).
The broilers were fed a nutritionally balanced diet from
1 to 21 d of age (initial phase) and from 22 to 42 d of age
(growing phase) formulated following the nutritional re-
quirements established for broilers under tropical con-
ditions by Rostagno et al. (2011) (Table 1). Through-
out the experimental period, the birds received water
and feed ad libitum. The chicks were vaccinated against
Marek’s disease, avian pox, infectious bursal disease,
and Newcastle disease, according to the Cobb( R©) vac-
cination program.

Design and Experimental Treatments

A total of 384 broilers were distributed in a com-
pletely randomized design in 2 climate chambers, one
with a perforated plastic floor and the other with wood
shavings. In each chamber, the animals were divided
into 16 boxes (8 with males and 8 with females) with

dimensions of 0.9 × 1.2 m each and an area of 1 m2,
which housed up to 12 birds per box.

Characteristics of the Floor Surface

The perforated plastic floor used in the present study
was identical to the one used for pig maternity floors.
The plastic floor was composed of a washable material,
with dimensions of 400 × 400 × 40 mm (length × width
× height), each unit weighed 1.55 kg, and had a resis-
tance up to 450 kg/m2. The plastic floor was mounted
on a wooden support, 0.5 m above the ground, to fa-
cilitate periodic scraping of waste. The wood shavings
used were from a pine processing plant, and this non-
toxic material was placed at a height of 5 cm for the
poultry litter.

Removal of Waste and Poultry Litter
Management

In the treatments with the plastic floor, waste was
removed once during the first week, every other d from
the beginning of wk 2, and daily from d 14 to d 42.
The cleaning was performed by sweeping below the
floor with a steel squeegee. The poultry litter (wood
shavings) was turned and stirred frequently to provide
greater incorporation of waste and prevent the forma-
tion of plaques.

Measurement of Ammonia and Carbon
Dioxide

For monitoring NH3 and carbon dioxide (CO2) con-
centrations, a Dräger Accuro R© gas pump (Draeger,
Houston, TX) coupled with colorimetric reagent tubes
was used. The concentrations of the gases were mea-
sured in the center of climate chambers, at the birds’
height, on d 28, 32, 35, 39, and 42.

Broilers’ Performance

The birds and feed were weighed weekly, with weight
gain (WG) (kg), feed intake (FI) (kg) and, subse-
quently, feed conversion (FC) determined. The eval-
uation of meat production (kg of meat for m2) and vi-
ability (% of live chickens on d 42) was based on the
methodology described by Oliveira et al. (2005).

Injuries Evaluation and Plumage Hygiene

For the evaluation of injuries, quality of locomotion
and plumage hygiene, the Welfare Quality R© Assess-
ment Protocol for Poultry (Welfare Quality R©, 2009)
was used. This protocol consists of attributing scores
for each factor by a trained appraiser at 42 d of bird’s
age. The number of birds evaluated was 6 per box (50%)

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PERFORATED PLASTIC FLOOR IN POULTRY REARING 3157

Table 1. Diet composition percentage and calculated nutrient values of experimental
broiler diets.

Ingredients(%) Initial Phase∗ Growth Phase∗∗

Corn 60.81 63.74
Soy chaff 45% 35.15 29.79
Soy oil – 3.12
Dicalcic phosphate 1.63 1.16
Limestone 0.84 0.76
Salt 0.42 0.44
L-Lysine HCL (78%) 0.25 0.21
DL-Methionine(99%) 0.29 0.23
L-Threonine 0.08 0.04
BHT 0.01 0.01
Vitamin and mineral supplement∗ 0.50 0.50
Total 100.00 100.00

Calculated nutritional composition
Crude protein (%) 21.27 18.86
Metabolizable energy (kcal/kg) 2.883 3.121
Ca (%) 0.85 0.69
Na (%) 0.19 0.20
Available phosphorus (%) 0.42 0.32
Methionine+ cysteine(digestible) (%) 0.88 0.77
Methionine (digestible). (%) 0.56 0.49
Lysine (digestible). (%) 1.22 1.05
Threonine (digestible). (%) 0.79 0.68
Tryptophan (digestible). (%) 0.24 0.21
Arginine (digestible). (%) 1.32 1.16

Nutrients per kilogram of diet: ∗From 1 to 21 d of—Vit. A, 7,000 IU; Vit. D3, 3,000 IU; Vit.
E, 25 IU; Vit. K, 0.98 mg; Vit. B1, 1.78 mg; Vit. B2, 9.6 mg; Vit. B6, 3.5 mg; Vit. B12, 10 μg;
Folic acid, 0.57 mg; Biotin, 0.16 mg; Niacin, 34.5 mg; Calcium pantothenate, 9.8 mg; Copper,
0.12 g; Cobalt, 0.02 mg; Iodine, 1.3 mg; Iron, 0.05 g; Manganese, 0.07 g; Zinc, 0.09 mg; Zinc
oxide, 6.75 mg; Selenium, 0.27 mg; Choline, 0.4 g; Growth promoter (Zinc bacitracin), 30 mg;
narasin + nicarbazin, 1 g; Methionine, 1.68 g. ∗∗From 22 to 42 d of age—Vit. A, 7,000 IU; Vit.
D3, 3,000 IU; Vit. E, 25 IU; Vit. K, 0.98 mg; Vit. B1, 1.78 mg; Vit. B2, 9.6 mg; Vit. B6, 3.5 mg;
Vit. B12, 10 μg; Folic acid, 0.57 mg; Biotin, 0.16 mg; Niacin, 34.5 mg; Calcium pantothenate,
9.8 mg; Copper, 0.12 g; Cobalt, 0.02 mg; Iodine, 1.3 mg; Iron, 0.05 g; Manganese, 0.07 g; Zinc,
0.09 mg; Zinc oxide, 6.75 mg; Selenium, 0.27 mg; Choline, 0.6 g; Growth Promoter (avilamycin),
7.5 mg; Monensin sodium, 0.1 g; Methionine, 1.4 g.

in a total of 48 males and 48 females per treatment, ran-
domly selected.

Animals were visually inspected and scores were as-
signed for the presence or absence of breast blister, hock
burn, and footpad dermatitis and, if present, the extent
of injury in each bird. Plumage hygiene was recorded
using a cleanliness score from 1 (“completely clean”) to
4 (“completely wet or soiled with litter material, feces
or dirt”), according to the amount of dirt impregnated
in the breast and legs of each bird. For the quality of
locomotion evaluation, birds were individually placed
on the floor and stimulated to move approximately 10
steps and a gait score from 0 (“normal, dextrous and
agile”) to 5 (“incapable of walking”) was given, accord-
ing to the animal’s ability to walk. All scoring systems
used followed Welfare Quality R© (2009).

Carcass Yield and Parts

For the analysis of hot carcass yield, all birds from
each experimental box were weighed, and then the av-
erage weight was calculated to remove 3 birds per box
(25% of the total number of birds housed) whose weight
was close to the average ± 5% by weight average, with
a total of 48 birds per treatment (50% males and 50%

females). The birds were identified by enumerated plas-
tic rings and subjected to eight hours of fasting in
preparation for slaughter. The birds were desensitized
with CO2, followed by the procedures of bleeding, scald-
ing, plucking, gutting, and cutting. The heavy parts
measured were the chest, back, thigh + drumstick,
and wing, in addition to the entire carcass. The car-
cass yield was based on the animal’s weight after fast-
ing and the weight of the clean carcass before cooling,
whereas the yield of parts was based on the weight of
the particular cut region by the weight of the clean
carcass.

Statistical Analysis

The means of weight gain, feed intake, feed conver-
sion, carcass and parts yield, meat production, and vi-
ability results were subjected to analysis of variance,
using Tukey’s test at 5% of probability using the SAS
(Statistical Analysis System) program. For the NH3 and
CO2 concentrations, graphics were produced with the
concentration curves of these gases over the production
cycles. For the scores of breast blister, hock burn, foot-
pad dermatitis, cleanliness, and gait the analysis, their
distributions per treatment and sex was used.

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3158 ALMEIDA ET AL.

0

5

10

15

20

25

30

28 32 35 39 42C
on

ce
nt

ra
tio

n 
of

 N
H

3 
(p

pm
)

Days

Wood Shaving
Plastic floor

Figure 1. Ammonia concentration (ppm) under thermal comfort.

400

600

800

1000

1200

1400

1600

28 32 35 39 42

C
on

ce
nt

ra
tio

n 
of

 C
O

2
(p

pm
)

Days

Wood Shaving
Plastic Floor

Figure 2. CO2 concentration (ppm) under thermal comfort.

RESULTS

Concentration of Ammonia and Carbon
Dioxide

The concentration of NH3 from 28 to 42 d of age is
shown in Figure 1. It was observed that the concentra-
tion of NH3 increased significantly in the wood shavings
treatment, with 5 ppm (28 d), increasing to 15 ppm on
d 32, 20 ppm on d 35 and 39, and presenting the highest
value on the d 42 (25 ppm). In the plastic floor treat-
ment, the concentration of NH3 gas remained almost
zero, on the d 28 showed the lowest value (0.5 ppm),
remained stable in 1 ppm on d 32, 35, and 39, and
reaching a maximum value of 2 ppm on d 42. The CO2
concentration also showed a gradual increase depending
on the production d (Figure 2). In the wood shavings

treatment, the lowest CO2 concentration (800 ppm) was
observed at the d 28 and 32, increasing to 1,000 ppm
(35 d), 1,150 at 39 d, and reaching a maximum value
of 1,400 ppm on d 42. In the plastic floor treatment
the lower CO2 concentration (600 ppm) was observed
at the d 28 and 32, increasing to 800 ppm (35 d), and
stabilizing in 1,000 ppm on d 39 and 42.

Performance

Broiler performance was measured by WG, FI, and
FC (Table 2). Chickens reared on wood shavings (7 d)
had a significant difference (P < 0.01) for FI between
males and females. It was observed that males presented
higher FI (0.186 kg) than females (0.174 kg). No signif-
icant difference (P > 0.05) was observed for WG, FI,
and FC between males and females reared on plastic
flooring.

On d 21, there was a significant difference (P < 0.05)
between males and females for WG and FI in the
wood shavings treatment, with males having higher
WG (0.895 kg) than females (0.828 kg) as well as for
FI, where males showed higher value (1.347 kg) than
females (1.259 kg). It was not observed significant dif-
ference (P > 0.05) for FC. In the plastic floor treat-
ment, there was a significant difference between males
and females for WG (P < 0.01) and FI (P < 0.05),
where males showed a higher WG (0.879 kg) than fe-
males (0.820 kg), as well as FI, where females showed
lower value (1.270 kg) than males (1.340 kg). It was
not observed significant difference (P > 0.05) between
males and females for FC.

At the end of the production cycle (42 d) there was
a significant difference (P < 0.01) for WG, FI, and
FC between males and females reared on wood shav-
ings as well as those reared on plastic flooring. In the
wood shavings treatment, males showed higher WG
(3.111 kg) than females (2.708 kg), as well as for FI,
where males presented higher FI (5.082 kg) than fe-
males (4.665 kg). These values of WG and FI resulted
into a better FC for males (1.63) than females (1.72).
In the plastic floor treatment, males showed higher WG
and FI (3.167/5.180 kg) than females (2.760/4.720 kg).

Table 2. Production performance of chickens raised in thermal comfort.

Wood Shavings Plastic Floor

Male Female P-value Male Female P-value

Weight Gain 7 d (kg) 0.120 ± 0.002 0.121 ± 0.003 0.7804 0.117 ± 0.002 0.115 ± 0.001 0.1911
Feed Intake 7 d (kg) 0.186 ± 0.003 a 0.174 ± 0.002 b 0.0149 0.168 ± 0.003 0.163 ± 0.002 0.3487
Feed Conversion 7 d 1.55 ± 0.027 b 1.45 ± 0.040 a 0.0309 1.43 ± 0.032 1.42 ± 0.028 0.6735
Weight Gain 21 d (kg) 0.895 ± 0.015 a 0.828 ± 0.009 b 0.0219 0.879 ± 0.007 a 0.820 ± 0.003 b 0.0001
Feed Intake 21 d (kg) 1.347 ± 0.019 a 1.259 ± 0.013 b 0.0225 1.340 ± 0.017 b 1.270 ± 0.010 a 0.0015
Feed Conversion 21 d 1.51 ± 0.008 1.52 ± 0.008 0.3105 1.52 ± 0.012 1.54 ± 0.008 0.112
Weight Gain 42 d (kg) 3.111 ± 0.013 a 2.708 ± 0.046 b 0.0002 3.167 ± 0.013 a 2.760 ± 0.022 b 0.0001
Feed Intake 42 d (kg) 5.082 ± 0.041 a 4.665 ± 0.082 b 0.0038 5.18 ± 0.087 a 4.72 ± 0.053 b 0.0003
Feed Conversion 42 d 1.63 ± 0.008 a 1.72 ± 0.005 b 0.0001 1.64 ± 0.024 a 1.71 ± 0.007 b 0.0091
Viability (%) 94.14 ± 1.516 98.92 ± 2.254 0.1153 100.00 ± 0.000 a 94.05 ± 1.537 b 0.0082
Meat Production (kg/m2) 35.922 ± 0.667 a 32.257 ± 0.827 b 0.0179 38.55 ± 0.162 a 31.64 ± 0.554 b 0.0001

Different lower case letters indicate significant differences in the column using Tukey’s test at 5% significance.

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PERFORATED PLASTIC FLOOR IN POULTRY REARING 3159

Table 3. Distributions (%) for the gait scores, injuries and
cleanliness.

Wood Shavings Plastic Floor

Male Female Male Female

Gait Score
0 0.0 0.0 0.0 0.0
1 0.0 2.1 0.0 0.0
2 12.5 39.6 12.5 25.0
3 79.2 54.2 54.2 64.6
4 6.2 4.2 31.2 10.2
5 2.1 0.0 2.1 0.0
Hock Burn Score
0 70.8 77.1 89.6 85.4
1 22.9 8.3 10.4 14.6
2 6.2 14.6 0.0 0.0
3 0.0 0.0 0.0 0.0
4 0.0 0.0 0.0 0.0
Footpad Dermatitis Score
0 75.0 58.3 68.7 50.0
1 10.4 27.1 14.6 20.8
2 12.5 14.6 14.6 22.9
3 2.1 0.0 0.0 6.3
4 0.0 0.0 2.1 0.0
Cleanliness Score
0 2.1 2.1 2.1 2.1
1 37.5 37.5 72.9 41.6
2 35.4 37.5 25.0 56.2
3 25.0 22.9 0.0 0.0

The values of gait score vary from 0 (normal, dexterous and agile)
to 5 (incapable of walking). Hock burn and footpad dermatitis scores
range from 0 (absence of lesion) to 4 (severe damage). Cleanliness score
ranges from 0 (completely clean) to 3 (completely wet or soiled with
litter material, feces or dirt) (Welfare Quality, 2009).

Meat Production and Viability

On the wood shavings treatment, no significant dif-
ference (P > 0.05) was observed for viability between
males (94.14%) and females (98.92%). However, males
had higher (P < 0.05) meat production (35.922 kg/m2)
than females (32.257 kg/m2).

For the plastic floor treatment, it was verified a signif-
icant difference (P < 0.01) for viability and meat pro-
duction, where males showed higher viability (100%)
than females (94.05%), and better meat production
(38.55 kg/m2) than females (31.640 kg/m2).

Quality of Locomotion

With respect to the gait score distribution (Table 3),
score 0 was not observed, and score 1 was found in
only 2.1% of females in wood shavings. Males from both
treatments had the same percentage of score 2 (12.5%),
while for females, differences were found, with higher
percentage (39.6%) of score 2 in the wood shavings
treatment than in the plastic floor treatment (25%).

Score 3 was observed more frequently for males in
wood shavings (79.2%) than for males in plastic floor
(54.2%). By contrast, in females, 54.2% showed a gait
score of 3 in wood shavings, compared to 64.6% in the
plastic floor. The score 4 was observed with higher fre-
quency in the plastic floor treatment for both males
(31.25%) and females (10.40%) than for wood shavings
treatment, which had a frequency of 6.20% and 4.16%

for males and females, respectively. Score 5 was not ob-
served among females in any treatment; among males
this condition had a low occurrence (2.1%) and was
evenly distributed between treatments.

Injury Scores

There were no animals affected by breast blister in
any of the treatments. Most of the animals did not
show footpad dermatitis either, especially among males,
which had 75% of score 0 in the wood shavings, and
68.7% in the plastic floor treatment (Table 3). The per-
centages of scores 1 was higher for females from both
treatments (27.1% vs. 20.8% for wood shavings and
plastic floor, respectively), than for males (10.4% vs.
14.6% for wood shavings and plastic floor). In general,
birds raised in plastic floors (males and females) had a
greater tendency towards footpad dermatitis with score
2 or above than the birds reared on wood shavings.

With respect to hock burn, in both treatments the
majority of the animals did not show any lesion, with a
higher percentage of score 0 in plastic floor treatment
than wood shavings, with approximately 90% of ani-
mals not affected. The score 2 was only found for wood
shavings, in 6.2% of females and 14.6% of males, while
scores 3 and 4 (severe conditions) did not occur in this
study.

Plumage Hygiene

For the cleanliness score, few animals were completely
clean, with 2.1% of score 0 for both treatments and
sexes. Most of the animals assessed were scored as 1 or
2. A clear trend of worse hygiene conditions in wood
shavings compared to plastic floor was found, for both
sexes, since birds reared on wood shavings showed a
lower frequency score of 1, which is considered suitable
in the industry. Furthermore, approximately a quarter
of the animals in this treatment was completely dirty
(score 3), which is an undesirable score in the industry
and was not found in any animal reared in plastic floor.

Carcass Yield and Parts

Males reared on wood shavings had a better live
weight (3.069 kg) than females (2.650 kg), as well as
eviscerated carcass weight (2.324 kg males vs. 1.987 kg
females), chest weight (0.940 kg males vs. 0.819 kg
females), thigh weight (0.647 kg males vs. 0.542 kg fe-
males), back weight (0.494 kg males vs. 0.421 kg fe-
males), and wing weight (0.229 kg males vs. 0.194 kg
females) (Table 4). No significant difference (P > 0.05)
was observed for relative weight (RW) between males
and females in all analyzed parameters.

On the plastic floor, males showed a better live weight
(3.225 kg) than females (2.730 kg), as well as evis-
cerated carcass weight (2.427 kg males vs. 2.062 kg
females), chest weight (1.005 kg males vs. 0.855 kg

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3160 ALMEIDA ET AL.

Table 4. Absolute and relative carcass yield and parts.

Wood Shavings Plastic Floor

Male Female P-value Male Female P-value

Live weight (kg) 3.069 ± 0.030 a 2.650 ± 0.030 b 0.0001 3.225 ± 0.028 a 2.730 ± 0.019 b 0.0001
Carcass weight eviscerated (kg) 2.324 ± 0.028 a 1.987 ± 0.021 b 0.0001 2.427 ± 0.022 a 2.062 ± 0.018 b 0.0001
RW of eviscerated carcass 0.757 ± 0.004 0.750 ± 0.003 0.1776 0.753 ± 0.005 0.755 ± 0.003 0.6622
Chest weight (kg) 0.940 ± 0.018 a 0.819 ± 0.014 b 0.0001 1.005 ± 0.013 a 0.855 ± 0.011 b 0.0001
RW of chest 0.404 ± 0.004 0.412 ± 0.005 0.2559 0.414 ± 0.004 0.415 ± 0.004 0.8873
Thigh weight (kg) 0.647 ± 0.007 a 0.542 ± 0.006 b 0.0001 0.672 ± 0.007 a 0.563 ± 0.008 b 0.0001
RW of thigh 0.279 ± 0.003 0.273 ± 0.002 0.1606 0.277 ± 0.003 0.273 ± 0.003 0.3820
Back weight (kg) 0.494 ± 0.007 a 0.421 ± 0.008 b 0.0001 0.510 ± 0.008 a 0.436 ± 0.006 b 0.0001
RW of back 0.213 ± 0.002 0.212 ± 0.003 0.8306 0.210 ± 0.002 0.212 ± 0.002 0.5325
Wing weight (kg) 0.229 ± 0.003 a 0.194 ± 0.002 b 0.0001 0.234 ± 0.003 a 0.198 ± 0.003 b 0.0001
RW of wing 0.099 ± 0.001 0.098 ± 0.001 0.6073 0.097 ± 0.001 0.096 ± 0.001 0.6119

RW = Relative weight (%)
Different lower case letters indicate significant differences in the column using Tukey’s test at 5% significance.

females), thigh weight (0.672 kg males vs. 0.563 kg fe-
males), back weight (0.510 kg males vs. 0.436 kg fe-
males), and wing weight (0.234 kg males vs. 0.198 kg
females). No significant difference (P > 0.05) was found
for RW between males and females in all analyzed
parameters.

DISCUSSION

The environmental conditions in the poultry facili-
ties are as important to the animals being raised as to
the farm workers. The NH3 measured in the air on the
wood shavings treatment at 42 d of age reached a higher
concentration (25 ppm) than the recommended by the
GLOBAL G.A.P (2016), which is the main program
of farm quality assurance in the world. This program
states that the concentration of NH3 in the air from
the production environment must not exceed 20 ppm.
Carvalho et al. (2011) found NH3 concentrations near
60 ppm when studying the influence of poultry litter
quality in the environment in broilers sheds. They re-
ported that this high concentration of NH3 in the atmo-
sphere was owing to the reuse of poultry litter, which
led to a further degradation of nitrogen compounds in
the litter material and hence an increased release of NH3
into the production environment. Traldi et al. (2007)
also observed a greater potential of NH3 volatiliza-
tion in reused poultry litter than in new poultry litter.
According to Bianchi (2013), high concentrations of
NH3 reduce the comfort of animals and cause problems
for their health, affect the durability of installations,
and reduce the safety and efficiency of the production
process.

According to the Brazilian regulation of workers
safety, the Standard Regulatory 15-Activities and un-
healthy operations (MTE, 2008), tolerable NH3 concen-
trations for humans is 20 ppm, with tolerated exposure
up to 8 h daily. However, Carvalho et al. (2012) showed
that when the NH3 concentration is above 10 ppm, the
feeling of irritation appears in the eyes and nostrils, and
recommended the use of masks throughout the man-
agement period within the poultry farm. In the present

study, the concentration of NH3 appeared to be out-
side the tolerable range for humans, indicating an un-
sanitary situation for workers when wood shavings are
used as the bedding material. However, low production
of NH3 obtained in the plastic floor treatment is an ex-
tremely important outcome, as NH3 was not produced
in high concentrations within the chambers having per-
forated plastic floors, leading to less detrimental effects
to animals and people living and working in the poultry
facility.

Concerning the CO2 concentration, an increase in the
CO2 in the atmosphere was observed in accordance with
the broiler’s growth, a result that concurs with the find-
ings of Henn et. al. (2015) that observed CO2 emis-
sions are proportional to live weight, and their rates
are proportional to weight gain. The concentration of
CO2 in the atmosphere with wood shavings was al-
ways higher than that observed in the environment with
plastic floors, caused by the microbial degradation pro-
cess of organic matter accumulated in the wood shav-
ings (Henn, 2013). Orrico Jr et al. (2010) noted that
the majority of the organic matter in poultry litter is
lost as water and CO2. In the present study, even in
the wood shavings treatments, CO2 concentrations re-
mained within the optimal range, which according to
GLOBAL G.A.P (2016) is 5,000 ppm for broilers, with
values above this representing a risk for animals. Henn
(2013) also observed levels (1,260 ppm) below the crit-
ical threshold of CO2 concentration in his study about
broiler chickens raised in poultry houses when utilizing
new wood shavings.

The data of this study showed that, as expected,
males showed better performance than females, with
higher WG, FI, and better FC, for both treatments. A
similar result was obtained by Andrews et al. (1990),
who studied the performance of broiler chickens on dif-
ferent surface materials, and observed higher WG in
males than in females. We also observed that broilers
reared on plastic floor treatment had WG and FI rela-
tively higher than observed for chickens reared on wood
shavings treatment. It was verified that males reared
on plastic floor were 56 g heavier than males raised on

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PERFORATED PLASTIC FLOOR IN POULTRY REARING 3161

wood shavings; as well females reared on plastic floor
were 52 g heavier than females raised on wood shav-
ings treatment. These results could be very important
in a practical and economic view. Males reared on plas-
tic floor showed a meat production 2.628 kg/m2 higher
than males reared on wood shavings; this data is very
important due the fact of being an expressive value.
If we consider poultry shed with 1,200 m2, we would
have an increase of 3,153 kg of chicken meat, taking
into consideration the total production area of broilers
worldwide, which represents an extra financial gain for
the producer. There was no significant difference in via-
bility between males and females reared on wood shav-
ings, but males reared on plastic floor showed higher
viability (100%) than females (94.04%). The larger via-
bility of males reared on plastic floor than males reared
on wood shavings can be collaborating with the higher
meat production of males reared in this system.

The results obtained regarding breast blister were
similar to those obtained by Garcia et al. (2012), who
observed no incidence of breast injury when evaluating
different types of materials (wood shavings, rice husks,
chopped napier grass) that might be used for poul-
try litter. Oliveira et al. (2002) also observed no effect
of bedding material on breast lesions in broilers when
studying 2 different types of poultry litter (wood shav-
ings and sawdust). For footpad dermatitis, our results
differ from those obtained by Kacher et al. (2013), who
compared the effect of plastic flooring and wood shav-
ings in duck production and showed lower frequency
of footpad dermatitis in animals raised on plastic floors
than in animals reared on wood shavings. In the present
study, the severe condition of footpad dermatitis (score
4) had low occurrence, and only in plastic flour treat-
ment. Additionally, plastic floor showed lower frequency
of animals (males and females) without footpad lesions,
compared to wood shavings treatment.

Regarding hock lesions, a possible cause of higher in-
cidence of this type of injury in birds reared on wood
shavings may be owing to the type of material used,
which is more abrasive than plastic floors that have a
smoother surface. Oliveira et al. (2002) studied the ef-
fect of using 2 different kinds of materials for poultry
litter (sawdust and wood shavings) and showed that at
a density of 10 birds/m2, the type of floor material did
not have any effect on the footpad and hock damage,
while the birds with density of 14/m2 had a higher in-
cidence of hock and footpad lesions to birds raised on
sawdust than birds rearing on the wood shavings.

The plastic floor management could be very impor-
tant for broilers hygiene. In the present study, the pres-
ence of a plastic floor improved the plumage hygiene,
once the broilers had a lower contact with feces. A bet-
ter hygienic situation in ducks reared on plastic floors
than on conventional litter was found by Karcheret al.
(2013). Akpobome and Fanguy (1992) studying broilers
on different types of poultry litter, also observed better
results with cleaning of the broiler feathers for those
poultry reared on plastic floors than for those reared
on wood shavings.

For gait score, there was no incidence of scores 0 and
1, that was associated with a very good locomotor qual-
ity and absence of walking disability. Most of the ani-
mals received scores 2 or 3, which was expected due to
the rapid growth in broiler chicken lines. Animals dis-
playing gait score 2 had an abnormality in their gait;
however, their ability to walk was not severely compro-
mised, being considered a moderate condition, whereas,
the scores 3 or above are conditions that must be con-
sidered important welfare issues, since animals have the
ability to walk compromised (Knowles et al., 2008; de
Jong et al., 2014, 2016). In the present study, higher
frequency of gait score 3 or above was found for plastic
floor, indicating that animals in this treatment tended
to have more locomotor problems than those raised on
the conventional litter (wood shavings).

A plausible cause for these findings is the low absorp-
tion of impacts on this type of floor material, and low
adherence of animals to the surface. When wood shav-
ings are utilized, the animals are on a soft substrate that
is capable of absorbing impact and gives more support
to the animal, promoting better development of the lo-
comotor system (Lensink et. al., 2013). Another possi-
ble explanation is the greater weight of the birds, since
according to Nääs et al. (2010), the limited mobility of
broilers is directly linked to the weight of the animal,
where heavier animals tend to show higher incidence of
locomotor issues than lighter animals. Fernandes et al.
(2012) observed a proportionality between the degree of
difficulty of movement and the weight of the animals,
where animals with higher locomotion scores (greater
difficulty in locomotion) showed a weight numerically
greater than animals with less limited mobility.

CONCLUSION

The findings of this study suggest that perforated
plastic floors could be a good alternative to substitute
wood shavings to raise broilers (male and female) since
it was efficient from the perspective of environmen-
tal conditions and production rates, promoting a bet-
ter quality environment and superior production rates.
However, more research must be conducted to study the
effects of perforated plastic floors on poultry welfare,
aiming to improve leg health, reduce footpad dermati-
tis and lameness of animals reared in this system.

ACKNOWLEDGMENTS

The authors are grateful to São Paulo Research Foun-
dation (FAPESP) for the financial support provided
(Process number 2011/16578-6).

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