Su Ba wrote:Ok, I'll take a stab at this. Just keep in mind that without examine the bird, this is going to be a wild guess.
The lack of neck feathers and the red pigmented skin appears to be normal since the birds have Turkin DNA. My own Turkins looked that this. The neck skin is thicker on the Turkins that other feathered breeds.
Your description of the blood under skin seems consistent with what is called a subdural hematoma. This is essentially a pool of "clotted" blood under the skin, often accompanied with edema (excess fluid in the tissues). The most common cause would be an injury. I can't begin to guess what that injury would be. Perhaps a fight. Perhaps a fall. Perhaps the hen slammed into something while trying to escape an attacker. Perhaps overly amorous attention from a rooster (roosters have been known to kill hen's, though not out of hatred).
Subdural hematomas usually don't cause problems, but I have seen some that became septic, thus killing the animal. Possibly this may be the case with this hen. Hard to tell.
This is along the lines of my thoughts
The photos remind me of what I call a blood tumor, my eldest dog once had one that grew on his neck until it burst, from my reading he was fortunate that it burst externally, internal bursting almost certainly means death, perhaps that's what happened to this hen
I've also read that it usually develops from getting some foreign matter into a wound that doesnt find it's way out
He later developed(and still has) another large tumor on his leg, I thought it was another blood tumor and given the circumstances of my living arrangement at the time I attempted to lance and drain this before it burst on my roommates carpet like the previous one did, this turned out to be a terrible idea as there appeared to be no blood to drain and I caused the poor dog unnecessary pain
Moral of my story was that i would not attempt to perform surgery to drain the growth
If possible spend more time observing to see if there is an overly aggressive bird or a plethora of sharp debris that could become lodged in the bird
Another thought off the cuff, perhaps a blood vessel burst under the skin?