I have one chick that I'm guessing may be a cockerel who is 4 1/2 weeks old, 5 weeks on Monday, that has stopped peeping like the rest and is making a sound like "chook, chook". Took me picking each up to eliminate who was making that sound. I always know when that one is talking! Is this a normal progression to it's grown up voice? My Sunny who's "chooking"