Effects of Nest Box Lighting on Nest Box Use in Four Commercial Layer Strains Reared Cage-Free

Laying hens exhibit strong motivations for environmental features including secluded nest sites and specific lighting conditions, yet research comparing preferences across commercial layer strains in cage-free systems remains limited. This study examined nest box use under four lighting conditions (monochromatic red LED, monochromatic blue LED, UVA LED, or dark) in four commercial layer strains—three White Leghorn strains (Hy-Line W36, Hy-Line W80, and Lohmann LSL) and one brown layer strain (Hy-Line Brown)—reared under identical cage-free conditions. Sixty birds per strain were housed in a single floor pen per strain (four pens in total), each with an eight-nest, two-tier nest box unit, and the location of eggs laid in nest boxes was recorded at 45 days during early lay. The percentage of eggs laid under each condition was used as an indirect measure of preference. Within each flock, lighting condition affected nest box use (p < 0.001). Overall, more eggs than expected by chance were laid in dark (33.12%) and red-lit (29.51%) nest boxes, and fewer in UV (21.46%) and blue-lit (15.91%) nest boxes. The three White Leghorn flocks used dark nest boxes most, whereas the Hy-Line Brown flock used red-lit boxes most (36.36%), and blue-lit boxes were the least used in all flocks. Use of top- versus bottom-row nest boxes also differed among flocks. Because each strain was represented by a single pen, strain and pen effects are confounded, and differences among strains should be considered preliminary and hypothesis-generating. Replicated studies are needed before strain-specific nest box lighting recommendations can be made.