I have two chickens who are 10 weeks old. One is a brown leghorn and the other chicken is a barred rock. I've had them for about 2 weeks now. In the past few days, I have noticed an amount of feathers being lost. I notice they probably have lost about 10-20 feathers a day the past 2-3 days, some large feathers and some small fluffy feathers. I haven't noticed any itching or biting type behaviors and they are eating and drinking what seems to be normal amounts. Is this a lot of feathers for them to lose?