MyHaven What about Gangrenous Dermatitis?
http://www.upc-online.org/poultry_diseases/62504gangrenous.htm
It does seem to be most common in fattening and growing birds but a couple of things stood out from the above article:
Gangrenous dermatitis (GD) sometimes seems to occur almost spontaneously in birds 4-8 weeks of age.
GD usually starts with the appearance of small pimples on the skin, soon progressing to involve large areas.
The breast, wings, rump and abdomen are most commonly involved.
In addition, there has been speculation that some of the slow feathering modern strains of birds (particularly male broilers) are more susceptible to GD because their skin is less protected due to the lack of feathers .. which might explain the lesions on the naked neck??
However, some of the pictures are pretty gross and probably not what you are experiencing but I thought it worth sharing, just in case.
Edited to add: The outbreaks are frequently observed in wet and warm premises. The gangrene could begin and involve the skin of the head, neck and the breast.
Well done, thanks. There are a lot of similarities and you picked them.
Started as pimple looking lumps which went dark very quickly.
The age of the bird is right. The lesions being on unfeathered areas fits.
The chicks would have been stressed as I'd just brought them home. I don't know what conditions they'd come from.
But the images I googled are of far worse conditions.
The below photos are the second chick that died. There is only two infected.
I took these photos a few hours after I found this little girl dead. When I found the chick the black patches in the photos were bright red.
It would be nice to know what it is so I know how to decontaminate.