I have 4 chicks, 3 are black and 1 is yellow. The chicks are around 2 months old and I let them stay outside in a safe place at night. I let them go outside a few days ago. Every night the yellow chick chirps but the other chicks are quiet. When I put them in the place they sleep, she stops chirping. Is she just used to being inside and wants to call me to get them up or is there another cause?