Nest use is influenced by the positions of nests and drinkers in aviaries.

The influence of the nest location and the placement of nipple drinkers on nest use by laying hens in a commercial aviary was assessed. Twenty pens in a laying hen house were equipped with the same commercial aviary system, but the pens differed in the nest location and the placement of nipple drinkers. Nests were placed along the walls in 10 pens, and nipple drinkers were installed in front of the nests in 5 of these pens. The other 10 pens were equipped with nests placed on a tier within the aviary (integrated nests). Nipple drinkers were installed in front of the nests in 5 of these pens. A total of 225 Lohmann Selected Leghorns were housed per pen. The hens were offered 4 nests per pen: 2 facing the service corridor of the laying hen house and 2 facing the outdoor area. The numbers of nest eggs and mislaid eggs were counted daily per pen. At 25, 36, and 43 wk of age, the nest platforms were videotaped and the behavior of laying hens in front of the nests was analyzed. The nest location affected the stationary and locomotive behaviors in front of the nests. Hens in front of the integrated nests and the nests with drinkers displayed more stationary behaviors than hens in front of wall-placed nests or nests without drinkers. No difference in the number of nest eggs could be detected, but the integration of the nests inside the aviary led to a more even distribution of hens while nest searching. In the pens with wall-placed nests, significantly more hens laid eggs in the nests at the wall near the service corridor than at the wall near the outdoor area. Due to this imbalance, crowding in front of the preferred nests occurred and pushing and agonistic interactions on the nest platforms were significantly more frequent. Placement of nipple drinkers in front of nests had no effect on the number of eggs laid in those nests.

Use of space by domestic chicks housed in complex aviaries.

To improve the understanding of the development of locomotor capacity in layer hens, we measured how female laying hen chicks (n=120) of four different strains (LSL-lite, Hyline Brown, Dekalb White, Lohmann Brown; 3 groups of 10 chicks per line) utilized the ground, the air, elevated horizontal (platforms and perches) and inclined surfaces (ramps and ladders) in an aviary until 9 weeks of age. We used infra-red video recordings to perform all-occurrences sampling of locomotive behavioural and perching events that occurred on the ground—where bedding material, food and water were provided, in the air, and on elevated horizontal and inclined surfaces within weekly 30-min sampling periods. Chicks preferred level ground during the first week of life compared to weeks 5–9 (P<0.0001) and performed 52% of all behavioural events in this section. Elevated surface use began at 2 weeks of age and increased over time (P=0.003), where most behaviour was performed in S2 (45% of all events). Chicks preferred horizontal to inclined surfaces, which were used from weeks 2–5 with maximum use occurring during weeks 2 and 3. Lohmann LSL chicks used the space above the ground most frequently (P=0.05) and performed more aerial ascent/descent behaviour than other lines (P<0.0001). Overall activity levels declined with age (P<0.0001). In summary layer chicks almost exclusively locomoted on the ground but utilized elevated horizontal surfaces (perch, first platform) as early as 2 weeks. These results provide information for improving space use in rearing aviaries by introducing lower perches, platforms and ramps/ladders to accommodate age-dependent locomotor abilities.

Do Zebra Finch Parents Fail to Recognise Their Own Offspring?

Individual recognition systems require the sender to be individually distinctive and the receiver to be able to perceive differences between individuals and react accordingly. Many studies have demonstrated that acoustic signals of almost any species contain individualized information. However, fewer studies have tested experimentally if those signals are used for individual recognition by potential receivers. While laboratory studies using zebra finches have shown that fledglings recognize their parents by their “distance call”, mutual recognition using the same call type has not been demonstrated yet. In a laboratory study with zebra finches, we first quantified between-individual acoustic variation in distance calls of fledglings. In a second step, we tested recognition of fledgling calls by parents using playback experiments. With a discriminant function analysis, we show that individuals are highly distinctive and most measured parameters show very high potential to encode for individuality. The response pattern of zebra finch parents shows that they do react to calls of fledglings, however they do not distinguish between own and unfamiliar offspring, despite individual distinctiveness. This finding is interesting in light of the observation of a high percentage of misdirected feedings in our communal breeding aviaries. Our results demonstrate the importance of adopting a receiver's perspective and suggest that variation in fledgling contact calls might not be used in individual recognition of offspring.

Influence of nest site on the behaviour of laying hens

Low rates of nest acceptance by laying hens are a major problem in commercial poultry farming operations with aviary systems, leading to costly manual collection and cleaning of mislaid eggs. To gain knowledge about factors affecting nest use, laying hens' preferences for different nest locations were tested. Nests are normally installed at one of two sites: against a wall of the hen house or integrated into one tier of the aviary rack The preferences of laying hens for different nest sites have never been examined under commercial conditions. The aim of this study is to investigate whether behavioural differences can be detected between the different nest sites. The study consists of two consecutive trials involving 5027 Lohmann Selected Leghorn hens (LSL) and 601 layer hybrids selected for extensive housing conditions (EXT). The hens were randomly assigned to eight compartments per trial in groups of 355-360 LSL or 300 EXT in a laying hen house. Four compartments were equipped with a Volito Voletage (R) aviary system (VV), and four were equipped with a Rihs Bolegell (R) aviary system (RB), both of which contained either integrated or wall-placed nests when the experiments started. A strongly balanced crossover design with four periods was used. At 36, 44 and 52 weeks of age, the nest site in four out of the eight compartments was switched. Before each change, the fronts of half of the nests were videotaped during the light period, and the behaviour throughout the main laying period was analysed. Furthermore, the numbers of nest eggs and mislaid eggs in each compartment were recorded every day. No differences in the number of mislaid eggs between the two nest sites could be detected, except at the age of 20/21 weeks when hens in VV aviaries mislaid more eggs when nests were integrated (P = 0.0012). More hens stood simultaneously in front of the integrated nests than in front of wall-placed nests (P = 0.015). Activity of the laying hens increased (P = 0.0073), and stationary behavioural patterns declined (P = 0.0093), when the nests were placed by the wall. Hens inspected integrated nests for a longer duration than wall-placed nests, but wall-placed nests were visited more frequently. In addition to the nest site, the width of the platform in front of the nest influenced laying hen behaviour. Compared with narrower platforms, balance movements decreased on wider ones. Additionally, the platform design had to be taken into account as well, given that hens could not stand or walk as securely on wooden slats as on a grid floor. (C) 2011 Elsevier B.V. All rights reserved.

Modification of aviary design reduces incidence of falls, collisions and keel bone damage in laying hens

Non-cage housing systems for laying hens such as aviaries provide greater freedom to perform species-specific behavior and thus are thought to improve welfare of the birds; however, aviaries are associated with a high prevalence of keel bone damage (fractures and deviations), which is a major welfare problem in commercial laying hens. Potential causes of keel bone damage are falls and collisions with internal housing structures that occur as birds move between tiers or perches in the aviary. The aim of this study was to investigate the scope for reducing keel bone damage by reducing falls and collisions through modifications of aviary design. Birds were kept in 20 pens in a laying hen house (225 hens per pen) that were assigned to four different treatments (n = 5 pens per treatment group) including (1) control pens and pens modified by the addition of (2) perches, (3) platforms and (4) ramps. Video recordings at 19, 22, 29, 36 and 43 weeks of age were used to analyze controlled movements and falls (including details on occurrence of collision, cause of fall, height of fall and behavior after fall) during the transitional dusk and subsequent dark phase. Palpation assessments (focusing on fractures and deviations) using 20 focal hens per pen were conducted at 18, 20, 23, 30, 37, 44, 52 and 60 weeks of age. In comparison to the control group, we found 44% more controlled movements in the ramp (P = 0.003) and 47% more controlled movements in the platform treatments (P = 0.014) as well as 45% fewer falls (P = 0.006) and 59% fewer collisions (P < 0.001) in the ramp treatment. There were no significant differences between the control and perch treatments. Also, at 60 weeks of age, 23% fewer fractured keel bones were found in the ramp compared with the control treatment (P = 0.0053). After slaughter at 66 weeks of age, no difference in keel bone damage was found between treatment groups and the prevalence of fractures increased to an average of 86%. As a potential mechanism to explain the differences in locomotion, we suggest that ramps facilitated movement in the vertical plane by providing a continuous path between the tiers and thus supported more natural behavior (i.e. walking and running) of the birds. As a consequence of reducing events that potentially damage keel bones, the installation of ramps may have reduced the prevalence of keel fractures for a major portion of the flock cycle. We conclude that aviary design and installation of specific internal housing structures (i.e. ramps and platforms) have considerable potential to reduce keel bone damage of laying hens in aviary systems.

Soft perches in an aviary system reduce incidence of keel bone damage in laying hens.

Keel bone fractures and deviations are one of the major welfare and health issues in commercial laying hens. In non-cage housing systems like aviaries, falls and collisions with perches and other parts of the housing system are assumed to be one of the main causes for the high incidence of keel bone damage. The objectives of this study were to investigate the effectiveness of a soft perch material to reduce keel bone fractures and deviations in white (Dekalb White) and brown laying hens (ISA Brown) kept in an aviary system under commercial conditions. In half of 20 pens, all hard, metal perches were covered with a soft polyurethane material. Palpation of 20 hens per pen was conducted at 18, 21, 23, 30, 38, 44 and 64 weeks of age. Production data including egg laying rate, floor eggs, mortality and feed consumption were collected over the whole laying period. Feather condition and body mass was assessed twice per laying period. The results revealed that pens with soft perches had a reduced number of keel bone fractures and deviations. Also, an interaction between hybrid and age indicated that the ISA hybrid had more fractured keel bones and fewer non-damaged keel bones compared with the DW hybrid at 18 weeks of age, a response that was reversed at the end of the experiment. This is the first study providing evidence for the effectiveness of a soft perch material within a commercial setting. Due to its compressible material soft perches are likely to absorb kinetic energy occurring during collisions and increase the spread of pressure on the keel bone during perching, providing a mechanism to reduce keel bone fractures and deviations, respectively. In combination with genetic selection for more resilient bones and new housing design, perch material is a promising tool to reduce keel bone damage in commercial systems.