Date of Graduation

8-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Thaxton, Yvonne V.

Committee Member

Christensen, Karen D.

Second Committee Member

Scanes, Colin G.

Third Committee Member

Wideman, Robert F. Jr.

Fourth Committee Member

Kuenzel, Wayne J.

Fifth Committee Member

Maxwell, Charles V.

Sixth Committee Member

Mauromoustakos, Andronikos T.

Keywords

Broiler; Infrared Thermography; Lameness; Stress

Abstract

The concept of broiler chicken welfare has evolved from a component of animal husbandry to a label on a chicken product package. Recent attention from the public has led to the need for higher welfare standards for animal production. A primary concern of broiler production is low activity/locomotion attributed to fast growth rates leading to poor leg health. To collect the scientific data necessary to determine conditions providing the best welfare for the bird, multiple methods of assessment are required. Stress is influenced by external (temperature, humidity, lighting, stocking density) and internal (metabolism, thermoregulation, hormonal balance) factors. This series of studies evaluated measures of health, stress and behavior. The main objective was to investigate noninvasive measures of broiler stress and lameness. The two primary noninvasive methods were extraction of the stress hormone corticosterone (CORT) from feathers to evaluate stress and infrared thermography (IRT) to evaluate stress as well as lameness attributed to bacterial chondronecrosis with osteomyelitis (BCO). First, an ELISA was used to measure the effects of CORT administration in the drinking water over a 72 hour period on CORT from serum, cecal contents, excreta and two feather types. The next series of studies evaluated light intensity and flooring type effects on broiler stress and leg health. Results from these studies indicate light intensity did not consistently affect the stress and leg health parameters that were measured. Rearing broilers on wire flooring is an effective method for inducing BCO lameness. While the wire flooring did induce lameness, it did not consistently affect stress or leg health parameters measured on sound broilers. The final study combined stress and lameness measures from previous studies to compare lame and sound broilers. In this study, statistical models were evaluated for their potential use in predicting lameness. The results from these studies suggest 1) the current method of extracting CORT from feathers is not useful to evaluate stress; 2) IRT measures of beak surface temperatures may be a useful method to evaluate stress; and 3) IRT measures of leg region surface temperatures may be a useful method to detect/predict lameness attributed to BCO in broilers.

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