From 27 to 49 days, half of the broilers
in green light and blue light were switched to blue light (G–B) and green light (B–G), respectively. The
levels of anti-Newcastle disease virus (NDV) and anti-bovine serum albumin (BSA) IgG in G–B group were
elevated by 11.9–40.3% and 17.4–48.7%, respectively, compared to single monochromatic lights
(P < 0.05).