Lump on Chickens Head, what is it?

[GooseLover27]

My chicken has recently developed a big lump on her head, it's hard and has no feathers on it. I was wondering if anybody had similar cases and knows what it is.

 

[thebanthams]

can it be tumor?

 

[GooseLover27]

I don't think its a tumor because she's still laying great, also the other hens are starting to get small naked spots on their heads and that's how hers started.