Factors affecting space use by laying hens in a cage-free aviary system: effect of nest lighting at pullet housing and of curtain nest color during laying.

At 17 wk of age, 1,800 Lohman brown hens were housed in 8 pens of an experimental aviary system, specifically set up for the purposes of the present study, and kept until 26 wk without or with nest lighting (lights inside the nest 1.5 h before the lighting of the installation) for training in the nest use. Then, at 27 wk, 4 combinations of nest curtains were adopted to evaluate the effects on hens' distribution, that is, nests with red (RR) or yellow (YY) curtains at all tiers; nests with red and yellow curtains at the first and second tier, respectively (RY); or nests with yellow and red curtains at the first and second tier, respectively (YR). The use of enlightened compared to dark nests at housing increased the oviposition rate (P < 0.001) and decreased the rate of broken (P < 0.001) and dirty eggs (P < 0.05) from 27 to 45 wk, while increasing the rate of eggs laid inside the nests (P < 0.001). The presence of yellow nest curtains increased the rate of hens on the floor in pens YY and YR compared to pens RR and RY (35.3 and 35.5% vs. 34.1 and 33.3%, respectively; P = 0.05) and the rate of floor eggs in pens YR (2.23% vs. 1.63 and 1.65% in pens RR and RY; P < 0.05). In pens RY, a higher rate of eggs was always found on the second tier compared to the first one with the most inhomogeneous distribution compared to pens RR, YY, and YR (+10.8 vs. +3.4, +1.9, and +4.6 percentage points of eggs laid on the second tier compared to the first one, respectively). In conclusion, nest lighting at housing trained hens to the use of nests while improving egg production in terms of quantity and quality. The use of yellow curtains on nests moved hens between the different levels of the aviary but this was not associated with an increased nest use for laying.