Hi..I have 6 backyard chickens. Had anyway. All speckle sussex. I live in Birmingham, AL. Temperature goes up to 100 F during the day. Nights are little better. As soon as coop door open automatically, they free range in the back yard. 22nd July, one of my chicken has died at night in the coop, with no prior evidence of stress/sickness/wound or anything. Coop door was closed. I have one fan in the ceiling, works all night to take moisture out. And window was cracked open. And I added another low blowing fan to direct to the roost. Now, 2 nights ago, again 11 pm. Another one, Bella, has died. Again with no apparent reason. I am confused and upset. Any experience, suggestions?