I heard a "bawk bawk bawgawk!" outside and I ran out to see what it was. I think it was Fiona, the oldest, making the loud noises. She does have the largest red comb. All of them are around 18 wk old white leghorns. She also squats. Her and the others who have large combs are also quite vocal. There are decoy eggs in the boxes. Do ready-to-lay chickens make quite a bit of noise?