My two-year-old chickens are moulting. Is this normal for this time of year? It's cold in november! I can't help but worry that they'll freeze with all their feathers falling out. But if that's a normal behavior for this time of year, I guess they'll be fine. But is it normal? They are losing a LOT of feathers! But not the new ones born this spring, just my older chickens and rooster. Thanks!