Effect of cross-wise perch designs on perch use in laying hens.

1. The use of cross-wise perches by laying hens was investigated in 8 groups of 6 hens. During a period of 5 weeks each group was exposed to 4 different perch arrangements: a single straight perch of 60 cm (P60), a 30-cm perch crossing the middle of another 30-cm perch (P30 + 30), crossing a 45-cm (P45 + 30) or crossing a 60-cm perch (P60 + 30). 2. Perch arrangement influenced perch use. Perch occupancy (the mean number of hens using the perches) was lowest in the P30 + 30 treatment during daytime, evening and night. Perch occupancy was lower for P45 + 30 than for P60 + 30 during daytime and for P60 during evening and night. Perch occupancy did not differ between P60 and P60 + 30. 3. Perch utilisation (perch use per unit of total perch length provided) was lower for the three cross-wise perch arrangements than for P60, indicating that the area near the crossing was not used optimally. 4. There were indications that the process of taking roosting positions was more disturbed with cross-wise perches. 5. Legislation and guidelines about the minimal perch length per hen should be refined to take into account the arrangement of the perches. A perch of 30 cm cross-wise to another perch should not be included in the total amount of perch length provided to the hens. For longer cross-wise perches, the precise distance near the cross that should be excluded remains to be determined.