Not an Emergency- weird tumor

[Mylied]

I had to put down this ~4 week old chick so this is for my own knowledge. It had this weird tumor growing on the back of its neck. Never saw this before. What do you think of it? It also had a leg twisted around backwards at the knee. We tried to fix it and then the tumor started growing.

 

[Dooziepen]

I had to put down this ~4 week old chick so this is for my own knowledge. It had this weird tumor growing on the back of its neck. Never saw this before. What do you think of it? It also had a leg twisted around backwards at the knee. We tried to fix it and then the tumor started growing.

View attachment 551773

Mine has a similar problem, but above it's wing. Did you ever figure out what it was?

 

[Mylied]

Mine has a similar problem, but above it's wing. Did you ever figure out what it was?

No. I think she had something wrong genetically. I had euthanized the chick after I discovered the growth, since she already had leg/walking problems. I didn't dissect the growth.