FLIR i7 thermal imaging camera that is used to photograph broilers in the lab.

A thermogram of a 2-week old broiler. NOTE: The lighter colours correspond to hotter surface temperatures – the legs in this bird are a main site of heat loss.

A 4-week old bird in a sitting posture. The feathers are more developed providing a good degree of insulation but the head and abdominal areas remain as locations where much heat is dissipated.

In addition to the University's ongoing research into the metabolic rate of broilers, energy balance can be better understood by measuring how much heat is lost by the birds to the environment.

The University of Manchester is able to track changes in heat loss as the birds age using infrared thermography. The special camera it uses (FLIR i7 infrared camera) detects radiation in the infrared spectrum.

Since the amount of radiation emitted by the birds increases with temperature, an image of spatial variation in temperature can be generated.

The university's researchers are particularly interested in how much heat the birds lose through their legs and feet since this might affect how the birds use behavioural changes to manipulate energy consumption, i.e. if they lose too much heat via the unfeathererd portion of the lower leg (tibiotarsus) perhaps they change posture to minimise the energetic cost of maintaining a high internal body temperature.

Additionally, feathers are developing fast as the broilers grow, so we can track how well insulated the bird is over development.

It can be seen how the warm bird stands out against the cooler background. Areas of interest in the photographs can be analysed to find how the surface temperature varies according to anatomical location and how this changes with ambient temperature.

By taking some simple anatomical measurements such as beak, leg and foot dimensions, the heat lost to the environment can be estimated using the thermal images taken with the camera.

The researchers expect that this method will offer an interesting perspective on broiler biology, helping to understand the link between temperature, energy consumption, chicken development and anatomy.