Huth, Jesse C (2015-05). The Effects of Pre and Post Hatch LED Lighting on Development and Behavior in Chickens. Master's Thesis.
Lighting is an important factor in raising poultry and has been shown to impact behavior as well as physical aspects of birds. To investigate how light may impact poultry embryos differently depending on egg shell color we conducted an experiment consisting of 4 hatches: 2 using a commercial white leghorn (W-36), and 2 using commercial broiler strains (Cobb 500 and Ross 308) eggs. Each trial consisted of 3 lighted (12L:12D) and 3 dark (0L:24D) incubators containing 288 eggs each. Hatchability and chick quality was measured, and 120 birds from each treatment in the Ross hatch trial were grown to 14 days and tested for behavioral and physical differences. All hatches showed significantly improved (P < 0.05) unblemished chicks in the lighted treatments, but only the 2 broiler trials showed greater hatchability when eggs were incubated under lighted conditions (90.12 +- 0.90%) versus dark (85.76 +- 1.58%). The only differences seen in the growout was a significantly lower asymmetry (light/dark: 0.90 +- 0.05 / 1.16 +- 0.07) and heterophil/lymphocyte ratio in the lighted treatments (light/dark: 0.28 +- 0.12 / 0.35 +- 0.11), both of which indicate reduced stress. A second experiment was conducted to determine how different types of lighting can affect broiler chickens during growth, consisting of 3 lighting treatments: Once LED, NextGen LED, and dimmable CFLs, with 120 broiler chicks in each. Broilers were grown to 45 days of age, and behavioral, welfare, and physical tests were performed throughout. Both LED treatments had lower tonic immobility and asymmetry scores (P < 0.05), as well as lower feed conversion ratio. Only the Once LED treatment had significantly lower H/L ratio and corticosterone concentration, as well as a higher eye height, cornea width, and 14 day bird weight. Spleen weight was lowest in the NextGen treatment and highest in birds under CFLs. Both LED treatments resulted in significantly lower plumage and hock scores than the CFL treatment, with the Once LED treatment also having a lower footpad score, indicating greater perceived welfare. Overall the results of this study show improved performance and reduced fear and stress under LED illumination.