Date of Graduation

12-2016

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor

Karen D. Christensen

Committee Member

Wayne J. Kuenzel

Second Committee Member

Colin Scanes

Third Committee Member

Fred D. Clark

Fourth Committee Member

Yvonne W. Thaxton

Keywords

Biological sciences; Broilers; Chicken; Light intensity; Light preference; Photoperiod; Welfare

Abstract

This project was performed in two parts. The first was focused on light intensity as it affects performance. A randomized complete block design (RCBD) was performed. Broilers, Cobb 500 (n = 1584) were housed in 3 commercial houses (121.9 x 12.2 m). In each house birds were randomized and placed in 72 pens of 121.9 x 121.9 cm (22 bird/pen, males and females). All the treatment groups were provided with 24h light (L) during the first week and then 18L:6Dark (D) and 20 lux from day 7 to 14. The 3 intensity treatments of 5 lux (lx), 10 lx and 20 lx (24 replications) with 18L:6D were started at day 14 and continued until 40 days of age.

The second experiment was designed to determine if birds showed a preference for light intensity while eating. A RCBD was performed with 3 different light intensities. Cobb 500 broilers (n= 180), were housed in 1 commercial house. They were placed in 6 pens. Each pen had 3 rooms with a specific light intensity and one feeder so the birds could choose under which intensity to eat after 14d of age. Feed disappearance for each feeder was collected and the lighting program was the same as in trial number one. Also a camera was set to record the feeding behavior of the birds (number of birds per treatment during one hour at a random time during the daylight period, before light turns off and one hour after light turns on).

In the first experiment there was no effect of light intensity on the production parameters. In the feed preference experiment there was a significant difference among the treatments (p<0.0001) in the total feed disappearance at the end (40 days) in which the 20 lx treatment showed the highest value. The feeding preference trial showed that the broilers prefer to eat under the 20 lx light intensity (p<0.05) in all the three times during the day.

The results suggest that from a welfare perspective meat-type broiler chickens prefer to eat and drink under 20 lx rather than 5 lx which is the common commercial practice. Results suggest that a greater attention to light intensity, particularly with respect to feeder placement, may not only benefit production performance, but also bird welfare due to their preference for increased light intensity when feeding.

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