Abstract
In commercial situations, laying hens must negotiate levels to reach resources such as food, water and litter. Providing ramps in aviary systems reduces collisions and resultant keel bone fractures in adults. We investigated whether providing ramps during rear improved the ability of birds to transition between levels.Chicks were reared commercially in two flocks both of which provided access to raised structures from three weeks of age. One flock had no ramps, but the other flock was provided with additional access to two types of ramp (wooden ladders, and grids formed from commercial poultry slats placed at an angle). At 8 weeks of age, 64 birds (32 from each rearing condition) were transferred to an experimental facility. At 10 weeks of age, 32 pullets from each group were trained to run to a food reward. During testing at 12–14 weeks of age the pullets accessed the food reward by moving up or down a ramp. The pullets’ behaviours and time taken to complete the task were recorded. Ramp use over three days was also observed in a room replicating a small-scale single-tier system. Four groups of 16 birds aged 12–14 weeks were housed for three days and the number of transitions between the raised tier and litter were recorded.For upward transitions, more ramp-reared birds than control birds succeeded in reaching the food reward for both ladder (52% vs 13%) and grid ramps (74% vs 42%). Birds from the ramp-reared group took significantly less time to complete an upwards transition (68.8s ± 49.3) than the control group (100s ± 37.6) (p = 0.001). In addition, the control group showed more behaviours indicative of hesitancy (moving away, head orientations, ground pecking and crouching) before transitioning, and signs of difficulty when making upward transitions (crouched walks, pauses, turning, returning and escape attempts). In the group housing observations, the ramp reared groups had almost double the number of transitions between the slats and litter on day one compared to the control group. This difference was reduced by day three.In summary, this suggests there are positive effects of providing ramp experience during rear shown by any combination of bird mobility, strength or cognitive ability leading to an increase in apparent confidence in older pullets. It is not known whether these benefits persist through to the laying period, but no detrimental effects were noted so we suggest that ramps should be included from the early rearing period onwards.
Highlights
In commercial loose housed laying systems in many European countries, ramps are increasingly provided to help birds with level changes in their environment
This difference was reduced by day three. This suggests there are positive effects of providing ramp experience during rear shown by any combination of bird mobility, strength or cognitive ability leading to an increase in apparent confidence in older pullets. It is not known whether these benefits persist through to the laying period, but no detrimental effects were noted so we suggest that ramps should be included from the early rearing period onwards
When considering the time taken to start a transition the control group took longer when faced with the Ladder ramp but there was no significant difference for the grid ramp
Summary
In commercial loose housed laying systems in many European countries, ramps are increasingly provided to help birds with level changes in their environment. In loose housed systems, increased collisions with the environment have been observed when a level change is included (Harlander-Matauschek et al, 2015). The addition of ramps in the laying house has been shown to reduce falls and collisions by 45% and 59% respectively, along with 44% of birds showing more controlled movements if provided with ramps (Stratmann et al, 2015). When negotiating a level change fewer hesitancy behaviours have been recorded in laying flocks provided with ramps spanning the full width of the lower tier (Pettersson et al, 2017a), suggesting that ramps can aid transitions between levels. Birds’ ability to negotiate ramps of different design has been trialled, showing easier transitions on a grid ramp and a preference for a grid ramp over a ladder ramp (Pettersson et al, 2017b)
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