Denmark’s Aarhus University is conducting a research project to find out if increasing incubation temperatures would reduce leg problems in broilers.
Scientists are set to examine whether the increased incubation temperature may increase the growth of supporting musculature and leg bones.
The demand for breast meat has put the industry’s breeding efforts to select chickens with a higher daily growth rate and more significant breast muscles. But leg muscles and bones do not proportionally grow with breast muscles, which may lead to slaughtering chickens that are having difficulty carrying their own weight.
“We expect that the project will help reduce the occurrence of leg problems in broilers and also reduce the number of chickens having to be put down because they have trouble walking. It will improve animal welfare as well as producer economy,” said senior researcher and project manager Niels Oksbjerg from the Department of Food Science at Aarhus University.
Previous studies demonstrated that an increased temperature results in an increased number of muscle fibers at day 18 of the incubation period. Muscle fibers constitute the basic building blocks of chicken musculature and are positively related to animal growth.
In order to examine whether or not an increased temperature will actually make a difference, the scientists plan to carry out a series of trials in which several groups of eggs are exposed to different incubation temperatures from day 4 to day 7 of the brooding period. Once they hatch, the chickens are weighed and this is repeated 15 and 35 days after hatching. The chickens’ feed consumption and mortality rate are also registered. Once they are put down, the chickens’ legs are weighed and the tensile strengths of their bones are measured.
“It has been observed previously that the number of limb movements increases in the period from day 6 to day 11 when the incubation temperature is increased. Muscle contractions and stretching increase the cell division in the muscles and therefore it seems likely that increased muscle activity may increase the number of muscle fibers and stimulate bone formation,” said Oksbjerg.