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An Exploration of Laying Hen Space Requirements: will Added Space Improve Living Conditions for the COmmercial white Egg Layer?

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	An Exploration of Laying Hen Space Requirements: will Added Space Improve Living Conditions for the COmmercial white Egg Layer?/
作者:	Alig, Benjamin Noble.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2023,
面頁冊數:	162 p.
附註:	Source: Dissertations Abstracts International, Volume: 85-01, Section: B.
Contained By:	Dissertations Abstracts International85-01B.
標題:	Physiology. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30516385
ISBN:	9798379870454

An Exploration of Laying Hen Space Requirements: will Added Space Improve Living Conditions for the COmmercial white Egg Layer?
Alig, Benjamin Noble.

An Exploration of Laying Hen Space Requirements: will Added Space Improve Living Conditions for the COmmercial white Egg Layer? - Ann Arbor : ProQuest Dissertations & Theses, 2023 - 162 p.

Source: Dissertations Abstracts International, Volume: 85-01, Section: B.

Thesis (Ph.D.)--North Carolina State University, 2023.

Avian welfare has recently become a major topic of research and debate. Within the egg layer sector, one practice that has come under scrutiny is the stocking density (space per hen) that is currently utilized for white egg laying hens. Many animal welfare and rights groups claim that hens do not have enough space to perform natural behaviors and that the lack of space causes harm to both the hen's body and mental state. The objective of this dissertation was to determine if lowering cage stocking density will improve performance, cleanliness, behavior, welfare, and health of commercial white egg layers raised in colony cages. We hypothesized that by lowing stocking density, hens would experience less stress and as a result, will display improvement in the parameters measured. Hens were kept in colony cages at densities of 208 in2 , 139 in2 , 104 in2 (closest to EU standards), 83 in2 , and 69 in2 (closest to current US density). Compared to the current used density, hens exhibited better egg production when give 208 in2 per hen. The densities between did not yield benefits. This study also discovered that hens given 208 in2of space per hen laid less USDA grade A eggs and more loss eggs compared to the currently utilized density. No differences in other egg production or quality parameters were observed between the currently utilized density and others. Microbial loads on the eggshell and cloaca were also taken as part of this research. We discovered that any increase of space per hen from the currently used density did not lessen or increase microbial loads including salmonella positives in either the cloaca or eggshell. For production and product safety, only minimal improvements were made after a dramatic increase in space per hen.To determine welfare; health, body condition and behavior were analyzed and observed. Increasing space per hen did not have an effect on feeding, drinking or foraging behaviors however, doubling the commercially used space resulted in more pecking inedible object behaviors. Tripling space per hen from the conventionally utilized density resulted in more stretching and moving behaviors however, there was no change in behavior from densities in between. Birds in the conventional density also crouched the most. Increasing space from the conventionally utilized density did not affect instances of standing, preening, feather pecking or sham dust bathing. Furthermore, aggression was found to decrease as space increased. For hen condition and health, this study analyzed stress, outward appearance, bone health, gut health, and fearfulness. We found no differences in stress parameters until the end of the study, where tripling space per hen resulted in lower corticosterone and heterophil lymphocyte ratios. We also discovered that hen space would need to be tripled to improve fearfulness reactions. We did not identify any differences in the expression of oxidative stress pathways. We further did not find any differences in bone health, villi measurements, tight junction proteins or pro-inflammatory factors. We did, however find that tripling space from the commercial density resulted in down regulation of anti-inflammatory factors. Finally, we did not see any differences in visual inspection of the beaks, keel, toe, foot, or combs across densities however, we did discover that feather quality did improve as space per hen increased.

ISBN: 9798379870454Subjects--Topical Terms:

518431
Physiology.

An Exploration of Laying Hen Space Requirements: will Added Space Improve Living Conditions for the COmmercial white Egg Layer?
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