Design of nest access grids and perches in front of the nests: Influence on the behavior of laying hens.

In aviary systems for laying hens, it is important to provide suitable nest access platforms in front of the nests, allowing hens to reach and explore each of the nests easily. This access platform is needed to achieve good nest acceptance by the hens and thereby prevent mislaid eggs. In the present experiment, the behavior of hens using 2 different nest access platforms, a plastic grid and 2 wooden perches, was examined. Furthermore, the nests were placed on both sides of the aviary rack (corridor side and outdoor side), either integrated into the aviary rack itself (integrated nest; IN) or placed on the walls of the pens (wall nest; WN), resulting in a 2 × 2 factorial design Four thousand five hundred white laying hens were housed in 20 test pens. The eggs in the nests and mislaid eggs were collected daily, and the behavior of hens on the nest accesses was filmed during wk 25 and 26, using focal observation and scan sampling methods. More balancing, body contact, and agonistic interactions were expected for nests with perches, whereas more walking and nest inspections were expected for nests with grids. There were more mislaid eggs and balancing found in pens equipped with nests with wooden perches. More agonistic interactions and balancing, less standing, and a longer duration of nest inspection were found with the WN compared with the IN. Interactions between platform design and position of the nests were found for duration of nest visits, body contact, and walking, with the highest amount for WN equipped with plastic grids. Nests on the corridor side were favored by the hens. Nest-related behaviors, such as nest inspection, standing, and walking, decreased over time as did the number of hens on the nest accesses, whereas sitting increased. These results indicate that the hens had more difficulties in gripping the perches as designed. The lower number of hens on the nest access platforms in front of IN may be due to a better distribution around nests and tier changes within the aviary rack. Based on these results, grids rather than perches provide for improved nesting behavior.

Influence of front curtain design on nest choice by laying hens.

1. The aim of this study was to investigate the effect of front curtains, one-piece (OP) or sliced in stripes (SL), on the hens' nest preference and laying behaviour in an aviary system. We predicted that hens prefer SL-nests as they could perform nest inspections and enter and leave the nest along its whole width leading to fewer conflicts and more settled laying behaviour. 2. Eight pens containing 20 White Leghorn laying hens were equipped with two roll-away nests, one with OP and one with SL curtains. Laying behaviour was recorded for two days at peak lay in weeks 25 and 26. 3. More nest visits and more nest entries and exits along the whole width of the nest were counted in SL-nests. More sitting events without egg laying were performed in the OP-nests. No differences were found in the number of hens visiting the nests, egg number or aggressive behaviour. 4. Hens appeared to value the seclusion and protection provided by a closed front curtain. However, sliced curtains provided more opportunities to perform nest inspections.

Comparison of the prelaying behavior of nest layers and litter layers.

The Swiss Animal Welfare Act decrees that the housing conditions of farm animals must guarantee animal welfare. In the process of developing a method to test nest boxes for their suitability for laying hens, we conducted an investigation using preference testing. It was aimed at verifying the occurrence of different types of layers within the same laying strain and to investigate the choice of a nest site. At the onset of lay, 24 individually housed hens were given the choice of 2 nest sites: a nest box or a litter tray. The chosen nest site and the behavior of the hen, 1 h prior to oviposition, were recorded at 3 stages during the period in which the first 20 eggs were laid. The majority (17) of the hens laid consistently in the nest box, and 7 hens laid consistently in the litter tray. Litter layers spent more time exploring during the hour prior to oviposition than did nest layers, and their final nest visit (when an egg was laid) was shorter. There was no significant difference in the number of entries into the chosen nest site between layers of the 2 types. As expected, the level of restlessness of hens decreased with laying experience. In the hour prior to oviposition, the frequency of foraging and resting increased, whereas the frequency of exploring and nest seeking decreased, and the number of nest-site visits declined. We conclude that there may be at least 2 different types of laying hens that show different nest-site preferences, with concomitantly different prelaying behavior.

Effect of the analgesic butorphanol on activity behaviour in turkeys (Meleagris gallopavo).

During fattening, the bodyweight of modern broad-breasted turkeys increases considerably within a very short space of time. In particular, the breast muscles increase disproportionately. This leads to a disadvantageous distribution in weight, and as a consequence, to a disturbed leg position and skeletal deformations like antitrochanteric degeneration, tibial dyschondroplasia, bending, twisting and rotation of the tibia, osteochondrosis, osteomyelitis, rickets, and epiphyseolysis of the femoral head increases. This cases of degenerative joint disease cause severe pain in humans and there are indications that this is also true for turkeys. The purpose of this study was to determine if behaviour indicative of such pain in turkeys of the B.U.T. Big 6 breeding line could be attenuated by administering a quick-acting analgesic, butorphanol. Twelve pairs of turkeys were tested at the ages of 7 and 12 weeks. One bird in each pair received an analgesic opioid injection, while the other one received a control injection of physiologically balanced saline solution. The time the birds spent putting weight on their legs, i.e., 'walking' and 'standing' and the distance covered by the birds were recorded during the 30 min periods before and after the application of the drug. At week seven the treated birds spent significantly more time putting weight on their legs than control birds. At week 12, the same tendency was observed. No significant differences were found in the distances covered by the animals. It is concluded that fattening turkeys reduce the time they are putting weight on their legs because these behaviours may be associated with pain.