Impact of Lighting Intensity on Welfare and Performance in Broiler Chickens

Lighting intensity (LI) affects broilers' behavior, circadian rhythms, physiology, and welfare, making it essential in commercial broiler management. This study evaluated the effects of three LIs (50, 20, and 5 lux) on Ross 708 and Cobb 700 broilers from day 8 to 56 in separate trials conducted under identical conditions. Growth performance (body weight (BW), feed intake, feed conversion ratio (FCR)) and welfare indicators (gait, feather condition, temperature, and footpad dermatitis were assessed biweekly. Ross broilers at 50 lux showed reduced BW on day 42 (<i>p</i> = 0.03), with no BW differences observed on day 56 (<i>p</i> = 0.14). FCR was unaffected by LI for Ross broilers. For Cobb broilers, BW was not affected by LI, though birds under 5 lux exhibited approximately 2.6% lower FCR on day 28 (<i>p</i> = 0.04) and 7.8% lower FCR on day 42 (<i>p</i> = 0.01). LI of 50 lux was associated with increased back temperatures, while bird at 5 lux showed better feather coverage and lower belly temperature (<i>p</i> < 0.01). Ross under 20 lux showed poorer feather cleanliness (<i>p</i> < 0.01), while those under 50 lux had better gait scores on day 56 (<i>p</i> < 0.01). These results demonstrate that production and welfare responded differently to LI, and that these responses also varied between strains. These findings contribute to sustainable poultry production by balancing welfare, efficiency, and growth.