At night when I go into the chicken coop to count them and lock the chicken door, I noticed that they are sneezing. I haven't heard it any during the day, only at night. It is getting colder here (November) it just started getting down to freezing at night, but we haven't had problems with them getting cold before. And, some of them have dried black-ish gray trails coming out of their noses. I just assumed they had chicken cold, but it has been going on for awhile. Any ideas?