ESR8: Early incubation temperature, embryonic development and welfare of broiler chickens


Selective breeding for a higher yield of breast meat has led to dramatic changes in the morphology of modern broilers compared to traditional types of chicken. Due to increased relative size of M. Pectoralis in relation to leg muscles, impaired gait is a common issue in broiler flocks, especially at the end of production. With animal welfare being increasingly demanded by the consumer and also being an ethical obligation when keeping animals, there is sufficient need to address this issue.
Studies suggest that by increasing the early incubation temperature from embryonic day 4 to 7 it is possible to affect the subsequent muscle and bone development, growth rate and welfare. It is possible to achieve a change in the number of muscle fibers in certain muscles, influencing the broilers’ ability to walk. In addition, manipulation with in ovo temperature may influence the genetic and/or phenotypic sex of the birds with possible effects on the production efficiency as well as meat quality traits.


  1. Identify and understand the effect of early incubation temperature of broiler chickens on embryonic development specifically sex and muscle development, in order to improve the animal welfare as well as production and meat quality traits.


  • Assessment of muscle development via growth factors, metabolic enzymes and histology,

  • Gait scoring,

  • Analysis of the dimensions and strength of the Tibia,

  • Assessment of meat quality via pH, water holding capacity, colour and texture,

  • Assessment of genetic and phenotypic sex.

Expected results

  1. Using the gained knowledge, a new incubation program will be suggested supporting a more sustainable broiler production with increased animal welfare, maintaining optimal muscle growth and meat quality (D1.10).

  2. The effect of incubation temperature on sex of broilers will be established (D1.4).

Planned secondments

  • At: PBS (4 mo); training in early sexing of chicks, phenotypic and genotypic;
  • At: SEGES (2 mo); training in novel methods on welfare evaluation in broilers.

Enrolment in Doctoral degree:

ESR8 will be enrolled at the Department of Food Science, Graduate School of Science and Technology, Aarhus University.