Assessment of the Effects of Stocking Density on Laying Hens Raised in Colony Cages: Part I—The Effect of Density, Time of Day and Hen Age on Behavior and Aggression
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsSee attached comments.
Comments for author File: 
Comments.pdf
Manuscript could benefit from minor grammar editing.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsAlthough great amount of work has been invested in presented study, it seems slightly anachronous. There are numerous papers studying behaviour and welfare of hens in enriched cages alone, or comparing cages and other systems.
The study, however, has a major flaw in experimental design. Together with stocking density authors changed also group size. Group size is an important factor, especially in smaller groups. Because these two variables (groups size and stocking density) are confounded, any results can be attributed to both.
Moreover, among behavioural parameters is missing severe feather pecking. This injurious pecking is major cause of welfare issues and should not be omitted.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe effect of stocking density on hen behavior and aggression. After reading this article, I think this research topic is in line with production practice, and it deeply explores the behavioral performance of laying hens with different stocking densities and ages to judge the welfare level of laying hens, which will provide a solid foundation for improving the welfare level of laying hens in daily production. However, I personally have some questions and opinions on the article as follows, please read and refer to:
- The title of this article is "The Effect of Stocking Density on Hen Behavior and Aggression", but the content of this article also includes a lot of information about the impact of different ages on the behavior of laying hens. The title of the article does not fully cover the main points of the article. Have you consider changing the title.
- The processing of test data includes statistical analysis. The article does not specify whether the statistical analysis has been tested for normality, because generally linear regression analysis is only applicable to data that conforms to the normal distribution. If the data conforms to the normal distribution, it must be indicated. If not, the data analysis is meaningless.
- Peck neighbor in Table 2 refers to aggressive pecking of hens in adjacent cages. Please check whether it includes pecking between hens in the same cage. If you are only discussing pecking between hens in adjacent cages, please explain why you only count the pecking behavior in adjacent cages, rather than the pecking between individuals in each cage.
- Lines 153-155: From the table, we can see that the frequency of laying hens pecking inedible objects is higher at night than in the morning and afternoon. However, in the article, you wrote that "the frequency of laying hens pecking inedible objects is higher at night than in the afternoon and at night". Please correct the incorrect statement of the result. In addition, the word "night" is replaced in the chart and the results. It is recommended that the chart and the text are consistent.
- Lines 320-324：There is no logical relationship between the two sentences. From the content of the text, it can be seen that there is no necessary connection between the contents before and after indicate. There is no causal relationship between pseudo-foraging, appetitive behavior and standing activity. It is recommended to consider the content of this paragraph as appropriate.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsFreedom to express normal behaviour is an element of animal welfare. Adequate space is required to ensure this. The amount of space available to laying hens is an animal welfare issue of concern to consumers, stakeholders and legislators. This is why this research is valuable. It shows under what stocking conditions birds are well behaved and able to express natural behaviour. The manuscript is well prepared. I have no critical comments. I have highlighted the only minor suggestions in the text of the manuscript.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThank you for revising the manuscript. No further revisions needed.
