Quantifying the optimal energy to protein ratio in diets of organic housed laying hens

The goal of this project is quantifying the optimal energy to protein ratio in diets of organic housed laying hens, thereby considering differences between summer and winter and the energy concentration of the diet.

Approach and timeline

Due to differences in housing conditions, climate conditions, behaviour and diet composition of organic housed poultry, energy and protein requirements may differ from conventional housed poultry. The environmental temperature in organic poultry houses and outdoors can be higher or lower than the thermal neutral zone of the birds. Reducing the temperature below the thermal neutral zone will result in an increase of the energy amount necessary for maintenance. Maintenance requirement may also increase as a consequence of more outdoor activities. In organic layer husbandry, the incidence of feather pecking behaviour is often higher, resulting in a lower quality of feather condition. A reduced feather condition results in a reduced insulation of the bird, leading to an increased maintenance requirement. When organic hens need less protein in their feed, this leads to a lower ammonia content of their manure, which fits in the idea of sustainable agriculture.


A layer house, containing 16 small pens with outdoor areas, is available to determine the energy/protein ratio in organic layer diets. The following questions will be answered:

  • What is the effect of organic conditions on energy/protein ratio? 
  • Differs the optimal energy/protein ratio in summer compared to winter? 
  • Is the optimal energy/protein ratio affected by the energy concentration of the diet?

The results of the project will be published in a report and in a technical paper in Pluimveehouderij.