Had to cull one of my pullets last night. They are in a mobile house so have fresh grass every day. I think they are about 14 weeks now so almost grown and all are looking fit and strong. Last night I looked in on them and one was off it's legs, head down with whitish gunk dribbling from it's beak. I took her out, decided to cull immediately and moved the house straight away. I took her back to the barn and popped her on the floor and when I picked her up there was a pool of the same gunk. All the rest look fine this morning.
Any ideas? We hatched them from bought in eggs. We have had Cocci in the past but it didn't look like that and they since we had it, we have been using medicated crumb to start them. Considering Mareks but that can't come through the egg I don't think and we've never had it here. No live birds have been bought in for about a year. at this stage I think (hope) that is unlikely.
Any other ideas? Feeling a bit on edge at the mo.