If their squatting and you've noticed the darkening comb, next they should start trying out their nesting boxes and soon you should start seeing eggsThey are squatting when I reach for them, one girl has a bigger comb recently and waddle and it's RED, dark red. I also noticed that their vents bulge a bit more than before. I try to get a once over a few times a week for monitoring health (vent, feathers, feet etc )
