My 9 black australorp hens are 3 years old. I have noticed a lot of feathers and I know that means they are molting, but how long does this last. I have not had an egg for 3 weeks. The weather has drastically changed in the last week to below freezing at night. I have put a light on for extra daylight and a heat lamp when it gets below 35 degrees. Please advise if this is normal and how long should I wait before I put them in the stew pot.