The Effect of Nest Box Curtain Color on the Nest Box Choice of Brown and White Layer Hens Breed in a Free-Range System * 1

Article No.: 063014284 DOI: 10.15580/GJAS.2014.6.063014284 In this study, the effect of nest box curtain color on the complex behavior of nest box choice of brown and white layer hens bred in a free-range system, an alternative breeding system to battery cages, was analyzed. Yellow, blue, red, and green curtains were placed randomly in the entrance of the nest boxes, and the color of the nest box curtain was observed to affect the egg-laying choices of the hens (P<0.01), while the curtain color x genotype interaction was determined to bear no significance. According to the results, the nest box choices of white layer hens were 36.53%, 17.54%, 15.42%, and 23.64% for red, blue, green, and yellow, respectively; these percentages were 35.01%, 17.52%, 17.66%, and 23.43% for the brown layer hens in the respective order of the colors. On the other hand, the percentage of eggs laid on the ground was determined to be significantly lower in both white and brown layer hens, compared to the control group (P<0.01). Submitted: 30/06/2014 Accepted: 18/07/2014 Published: 18/07/2014


INTRODUCTION
Eggs laid on the ground pose a significant problem in the alternative hen breeding systems other than battery cages (Zupan et al., 2005).Furthermore, nest acceptance rates are low in laying hen husbandry, and this increases the rate of eggs laid on the ground (Lentfer et al., 2011), 10% in percentage (Kathle et al., 1996).Laying eggs on the ground increases the risk of the eggs cracking and breaking, causes the eggs to be more contaminated with bacteria.Further, more time and labor is required to collect eggs.The nest choice of layer hens is a very complex behavior, and is affected by several factors (Zupan et al., 2005).
Before laying eggs, hens search for a possible and an alternative nest to lay eggs; and finally they arrange the nest they choose with their feet and beaks, and lay eggs (Petherick and Rushen, 1997).This procedure takes one or two hours (Keeling, 2002).
Nest box design has an effect on nest box choice (Cooper and Appleby, 1996), but animal species, individual differences, age, and nest box usage experiences during breeding period also have an effect in determining the nest box use behaviors of poultry (Duncan et al., 1978).Further, Egg laying behaviors were presented to be affected by the color of the nesting box for the broilers (Brake, 1993), while the nest box choice could be manipulated in quails (Schmid and Wechsler, 1998).One of the interesting aspects of nest box choice is the preference of nest boxes filled with eggs, instead of those that are empty, and this is called social nesting (Riber, 2010).Subject Judging from another angle in spite of the fact that knowledge of egg production systems is poor among consumers, they are willing to pay more for eggs produced in systems bearing trendy names related to healthier, safer alimentation (designer eggs, enriched eggs) or traditional farming systems (organic, freerange, barn, etc.) (Parrott, 2004).
This study was carried out to determine the effect of nest box curtain color on nest box choices of native brown and white layer hens bred in a free-range system.

MATERIALS and METHODS
Animal, diet and management: Two different native layer hen lines (Line 54 is brown and Blue is white layer hens) bred at the Ankara Poultry Research Institute, and brought to Poultry Unit of the Agricultural Faculty of Ahi Evran University was selected for the study.The temperature during the study period was between 18.4 •C -6.8 •C (for nights, minimum) and 29.4 •C (for daytime, maximum).No predator attack was experienced, and potential predators were not observed.Standard care , feeding , and breeding procedures determined by the Ankara Poultry Research Institute was applied to the birds, and their health controls were conducted throughout the testing period.The free-range breeding system was applied in the test.A total of 320 animals, 26 weeks old for 12 weeks, were bred in 3 repetitions, 40 animals for each repetition and in the control groups of brown and white layer hens.In the control group, all the conditions are the same, although there are no curtains in the nest.Each repetition had two-story nests with a total of 8 boxes.Colored curtains which made of satin fabric with four slits were placed randomly on the open entrances of the nest boxes.Measurements of curtain fabric colors of reflectance were taken using a spectrophotometer (Datacolor Mercury 2000).They did provide the same degree of darkness to the nest-box that using light meter.Wooden nest houses were designed in the size of 0.40 m x 0.40 m x 0.40 m, and wheat stems were placed on the ground of nest boxes.
The peak point of egg production was determined to be ≥ 0.9 egg/day per hen (Riber, 2012).Eggs were carefully collected from nests four times a day.Settlement density was 1.2 hens per m 2 .During the testing period, the animals were allowed to go outside of the closed areas between 08:00 and 17:00.Forty animals from each genotype were placed in 2 m x 6 m closed areas and 2 m x 18 m open areas, and their choice of nest boxes was determined.A bell type automatic drinker providing ad libitum access to drinking water and a standard commercial layer hen feed were placed in each nest box division, in accordance with the period, and a 16-hour period of light was ensured.

Statistical Analysis:
The rates of laying eggs in red, blue, green, and yellow curtained nest boxes and on the ground were determined in percentages for brown and white layer hens subject to free-range system, using the data recorded during the test period.Homogeneity test and angle transformation was applied to the data determined in percentages, without applying any variance analysis.A significance test was applied according to genotype (a), and curtain color in the nest box (b), and their interaction with each other, in accordance to the randomized blocks factorial testing design.Mathematics model of this design is given below.
The difference between the averages was determined according to the Duncan multiple comparison test.The analyses were tested using SPSS 14.0 package program.
The mathematical model of the test is: = j level effect of B, (αβ)ij = interaction effect between the i level effect of A and j level effect of B, eijl = random error of Yijl.

RESULT and DISCUSSION
The descriptive statistics of genotypes are given in Table 1.According to the results given in the Table 1 it is observed that white layer hens mostly preferred red (37.051%), while this color was followed by yellow (23.63%), and blue (17.45).On the other hand, the lowest rate was attached to laying eggs on the ground (6.96%).Accordingly, the color red had an effect on the white genotypes.In terms of the standard deviation of the characteristics analyzed in the study, the lowest rate was observed in the control group.Nevertheless, the highest standard deviation value was observed in the color yellow.Variance in the color yellow was very high due to the standard variation, while the coefficient of variation was determined to be medium due to the high average.On the other hand, variance and variation coefficient of the color red was observed to have the lowest value after control group.In any case, change in the color red is observed to be lower when the lowest and highest values are considered.Meanwhile, there was no statistically significant difference between floors.According to the table 1, brown layer hens for the results are parallel to the results observed in white layer hens.Accordingly, the color red is the most effective color for brown layer hens and for the white ones.And similarly, the high variation rate of yellow curtain is remarkable.On the other hand, coefficient of variation was determined to be higher in brown layer hens compared to the white ones.
Figure 1 demonstrates the distribution of egg rates of white layer hens according to colors.Determination of the control group can be clearly observed in this figure.However, the most remarkable point is the color yellow.Due to the high rate of variation, it approaches both the color red, and to the values of egg-laying.In this sense, it is concluded that it must be carefully monitored in order to assess this variation in the positive way for the color yellow.

Figure 1: Distribution of the eggs in white genotype
Figure 2 demonstrates the effects according to the main component scores of white layer eggs.According to the figure, the color red and yellow have positive and increasing effects.This effect of the color yellow results from the wideness of the variation, as stated above.It can also be concluded that the color blue has a significant decreasing effect, while the color green has low increasing effect and that this effect decreases.According to this figure, the effects of the colors red and yellow in brown genotypes change places, compared to their effects in white genotypes.However, at this point, the color red has a positive and increasing effect, while the color yellow has a negative and decreasing effect.On the other hand, the color blue has a negative effect, while the effect of the color green was determined to be insignificant.

Figure 4: Effects according to the main component scores of brown layer eggs
Table 2 demonstrates the variance analysis of egglaying according to the genotypes.According to the chart, the curtain color of the nest boxes was determined to bear significance in the nest choices of hens (P<0.01), while the genotype and nest curtain color x genotype interaction were determined to be insignificant.As can be seen on the table, the color red has the highest value for both white and brown genotypes, and this indicates that it is an effective factor.However, the colors blue and green were included in the same group, and ranked second after the color red.The color yellow had a far lower value compared to the other colors.Accordingly, the color red is a more indicative color, compared to the others.2011)'s research they do the majority of chickens to lay eggs in nests were selected (90.59%).This rate has been found in our study.This is a natural behavior based on the nest box material and in nest position (Cooper and Appleby, 1997;Zupan et al., 2008).
In a study carried out to reduce the rate of laying eggs on the ground, and to analyze the nest box choices of two different hen races for the colors blue, green, yellow, and red, the rate of egg-laying on the ground dropped dramatically after placement of colored nest boxes, and 3.7% and 5.8% reduction was observed in race 1 and 2, respectively (Hurnik et al., 1973).This study is parallel to the current study in reducing the rate of egg-laying on the ground.
It is remarkable that the variation of choice for the nest box with the yellow curtain was high for both races.In further studies, both appealing and repellent effects of the color yellow can be studied using different shades of yellow.
Sharing the nest boxes simultaneously may cause social problems among laying hens, and egg production may be negatively affected (Riber, 2012).Furthermore, plasma or albumen corticosterone level, which is accepted to be the physiological stress indicator in terms of animal welfare, increases when there is no access to nest box for egg-laying, or when the number of nest boxes is insufficient (Greg et al., 2012).According to the results of this study the use of colored curtains affects the choice of nest boxes, and hence can solve the problems related to simultaneous nest box sharing.These results in preferred nest, not only shadowing effect of the curtain the, also color curtain is effective.This issue should be investigated in more detail.

CONCLUSION
It was concluded that the use of colored curtains in nest boxes can be recommended for native white and brown layer hens bred using a free-range system in order to reduce the rate of egg-laying on the ground with lower discarded (cracked and broken) eggs.The use of colored curtains can be addressed as a reliable system to improve laying performance for nest box and behaviour of laying hens in free-range systems.Consequently, with this application it can be assessed laying hens in free-range systems, to improve breeding programs to perform different behavioural and welfare studies.The integration with colored curtains by the nest boxes the needs of the hens for not on the ground to laying will be less than non-curtain nest boxes.This system can be modified the use of different colored curtains on nest boxes.

COMPETING INTEREST
We had full access to all study data, take full responsibility for the accuracy of the data analysis, and have authority over manuscript preparation and decisions to submit the manuscript for publication.None declared under financial, general, and institutional competing interests.

Figure 2 :
Figure 2: Effects according to the main component scores of white layer eggs

Figure 3 :
Figure 3: Distribution of the eggs in brown genotype

Table 1 : Descriptive statistics of variables in genotypes
1 SEM = Standart Error Mean

Table 2 : Variance analysis of egg-laying according to the genotypes
Means within lines with different superscripts differ at p<0.01 Table3revealed the variance analysis of egg-laying according to the curtain colors.The curtain color of the nest boxes is significant as statistically (P<0.01).The curtain color has the highest value in the nest choices of hens.Table4shows results of multiple comparison tests according to curtain color.As can be seen on the table, the color red has the highest value for laying hens.