Ok I need some help guys, I've been trying to do the research online but I'm coming up with nothing. In the past week I've had 2 chickens die. They have like a big white s sack down by their rear. When we first notice the sac it was about 3 days later n they died. Also it's winter here. We do have a heat lamp in the coop with them. We usually have about half the eggs we usually get in the summer but the past week we're lucky if we get 2 a day. Today nothing so far. I did take in my brothers chickens ( he had 3 that were free range never penned up ). I don't notice any other symptoms besides what I'm describing. Any help on this would be greatly appreciated. Maybe I'm not noticing something. Thank you in advance.