Due to the genetic selection for a high growth rate of progeny, broiler breeders have a high growth potential and need to be feed restricted to prevent health and reproduction problems at later ages. Low-density diets may improve welfare of restricted fed broiler breeders by increasing feed intake time with less frustration of feed intake behaviour a result. Moreover, low-density diets may promote satiety through a more filled gastrointestinal tract, and therefore feelings of hunger may be reduced. In this experiments broiler breeders were fed 4 different diets during the rearing and laying periods. Behavioural and physiological parameters were measured at different ages as indicators of hunger and frustration of the feeding motivation. A diet of 8.4 MJ/kg as compared with a standard diet of 10.9 MJ/kg extended feeding time and reduced stereotypic object pecking at 6 and 10 wk of age. Furthermore, compensatory feed intake at 12 wk of age was reduced. During lay, differences in behaviour were observed between the treatments that could be attributed to differences in feeding time. However, birds fed the diet with lowest energy content (i.e. 9.2 MJ/kg) had higher heterophil to lymphocyte ratios at 40 wk of age compared to other treatments, indicating that they experienced more stress during the laying period than the other treatments. This result could have been due to the very long feeding time of this treatment group during lay, which may be stressful. In conclusion, a low-density diet of 8.4 MJ/kg may reduce hunger and frustration in the first half of the rearing period. However, for substantial improvement of broiler breeder welfare during rearing, more extreme diet modifications are required.