Pressure load on keel bone and foot pads in perching laying hens in relation to perch design

Abstract

The provision of perches in housing systems for laying hens is meant to improve hens' welfare by allowing a more natural behavior repertoire. However, the use of perches is associated with welfare problems, such as keel bone deviations and foot pad lesions, that may possibly result from high mechanical pressure load during extended perching activities. The aim of this study was to analyze peak force and contact area of hens' keel bones and foot pads on solid test perches of square, round, and oval shape with 3 different diameters each (experiment 1) and on commercially used perches (round steel tube, 2 sizes of mushroom-shaped plastic, and flattened round plastic) together with 2 prototypes of soft, round polyurethane perches (experiment 2). Test perches were covered with a pressure sensor film and 36 laying hens (18 Lohmann Selected Leghorn, 18 Lohmann Brown) were consecutively placed on each perch in an experimental cage during nighttime. Peak force (N/cm(2)) and contact area (cm(2)) were measured while hens were sitting and standing on the different test perches. Pressure peaks on the keel bone were approximately 5 times higher compared with single foot pad. On square perches, keel bone peak force was lower (P < 0.05) and contact area was larger (P < 0.001) compared with round and oval perches. In addition, peak force on foot pads in standing hens was higher on square perches (P < 0.05) compared with oval perches. Perch size did not affect peak forces on keel bones in sitting hens and foot pads in standing hens (experiment 1). On prototype perches, peak force on the keel bone was lower and contact area was larger compared with all commercial perches tested (P < 0.001). Peak force on foot pads was lower on prototype perches compared with steel perches (P < 0.01; experiment 2). Perches with a soft surface may possibly reduce keel bone and foot pad welfare problems in perching laying hens.

Associations between and development of welfare indicators in organic layers

“…Keel bone damage is a term covering both keel bone deviations and keel bone fractures. Long-term pressure on the keel bone, especially on poorly designed perches, is one identified factor causing keel bone deviations (Tauson and Abrahamsson, 1994;Pickel et al, 2011), whereas keel bone fractures are likely to be caused by collision with housing equipment or other hens (Freire et al, 2003;Sandilands et al, 2009;Stratmann et al, 2015).…”

The welfare of layer hens in cage and cage-free housing systems

“…Poorly designed and maintained perches have been associated with bumblefoot due to an accumulation of droppings and litter (Lay et al, 2011), and perches in furnished cages have been associated with an increased risk of cloacal cannibalism. Pickel et al (2011) investigated perch shape and type and the effects on hens' keel bones and foot pads. Certain designs, such as those with a soft surface, larger surface area, and a hygienic surface may be important in minimising risks to keel bones, foot health, and subsequently hen welfare (Pickel et al, 2011).…”

“…Pickel et al (2011) investigated perch shape and type and the effects on hens' keel bones and foot pads. Certain designs, such as those with a soft surface, larger surface area, and a hygienic surface may be important in minimising risks to keel bones, foot health, and subsequently hen welfare (Pickel et al, 2011).…”

Scientific Opinion on welfare aspects of the use of perches for laying hens

“…The use of cool perches therefore has the dual purpose of meeting behavioural hen demands for perching, and controlling, or moderating, the impact of heat stress episodes. Although warm perches have a similar potential to be used as heating devices, so far only one study has looked at its effect on resting and comfort behaviour (Pickel et al, 2011).…”

“…The effects of perch surface temperature (15, 18 and 28 °C) Pickel et al (2011) analysed the effect of varying the perch surface temperature on resting behaviour and comfort by manipulating the temperature of the water passing through the perches, with temperatures of 15, 18 (room temperature) and 28 °C. Perches were galvanised steel pipes 34 mm in diameter.…”