[Planimetric measurement of floor space covered by pullets]

The available floor space has a strong impact on the execution of various behaviours of laying hens. Presently, in Germany detailed requirements on the housing of pullets are insufficient. In order to get a first approximation, the floor space covered by pullets was determined by the colour contrast planimetric method KobaPlan. The measurements on standing and sitting pullets were done on a random sample of Lohmann Brown (LB), Lohmann Tradition (LT), Lohmann Selected Leghorn (LSL) and Dekalb White (DW) hybrids from the 6th week of life to 18/20 weeks at regular intervals. The hens were weighed and photographed digitally in a specific planimetric box (n = 2600 photographs from pullets in standing and 1360 in sitting position). Afterwards the KobaPlan software program calculated the animal area.The results showed a correlation between floor space covered by the pullets in standing position and the live weight (R2 = 0.80-0.96). The mean floor space covered by LB and LT at the end of rearing (body weight 1450 +/- 25 g LB and 1500 +/- 25 g LT) was 422.4 +/- 41.9 cm2 (LB) and 446.7 +/- 49.0 cm2 (LT) stand- ing, respectively 448.0 +/- 51.0 cm2 (LB) and 464.5 +/- 42.6 cm2 (LT) sitting. LSL and DW (body weight 1300 +/- 25 g) used 371.0 +/- 41.3 cm2 (LSL) and 349.3 +/- 26.3 cm2 (DW), respectively in standing and 379.5 +/- 41.2 cm2 (LSL) in sitting position. Maximum stocking density recommendation for pullets based on these planimetric results compared with the space allowance in alternative housing systems for laying hens are between eleven and 14 birds/m2. To verify this stocking density recommendation for pullets further studies should be complemented by specific ethological observations.