Nest building test

The nesting test was performed as described [45, 46] with modification. In brief, two nestlets (5 g) were placed into the cage at 1 hr before the dark cycle, then the nest score and the weight of unshredded nestlets were determined after overnight. Nest construction was scored on a six-point scale. The nests were scored by two independent observers blinded to the group according to the following scale: 0= undisturbed; 1= disturbed; 2= flat nest; 3= cup-shaped nest; 4= incomplete dome; 5= complete dome.