I have been feeding fermented feed for a few months now. I have 10 hens. I feed 2 times a day, about 10 - 11 cups total.The last 2 days they are not eating as usual. Half the fermented feed is left over. The feed smells and looks as usual. The girls are all acting fine, I am getting between 7- 10 eggs a day. I have not increased snack and only very limited scratch when it is really cold. Why are they not eating? Can the feed be bad??