I have lost 5 adult chickens in the last week, one moment they're fit and healthy, the next thing they're dead! No symptoms previously.
I lost my biggest last week (18 months old) and he was just lying dead in the middle of their feeding area, I thought he may have had a heart attack. The following day I lost another smaller cockerel (5 months old), then a gap of a few days where all was fine and then yesterday two were dead in the coup lying side by side, one beautiful 8 month old hen and a further young cockerel. Today there is a young cockerel dead in the nest box inside the coup.
I have cleaned and disinfected twice since the second one died. I did think the first two had noticably purple combs once dead, but I'm not so sure this is anything out of the ordinary now as the last few look "normal". We live in the Canary Islands in Spain, and it is hot at the moment, but nothing that they've not been used to before. And it appears they are dying in the night when it is cooler.
Any help greatly appreciated! Thank you in advance.