Auracana chick with lump on its head.

[Quack and Squeak]

Hello everyone.
I've had this issue before with a silkie years ago and just checking if this is an OK thing.

At a first glance it may just look like feathers but I'll put a photo below of one of the others that doesn't have a lump.

I'd be glad if anyone could tell me if they've had it before or if it can harm it. It's perfectly well and healthy outwardly.

 

[NatJ]

It looks to me like the vaulted skull that can happen on chickens with a crest of feathers on their head. That would explain why you also saw it on a Silkie in the past.

What country do you live in?
I live in the USA. Araucanas here are not supposed to have a crest.
But in some other countries Araucanas do have a crest on their heads (same breed name, very different appearance.)

If your Araucanas are crested, then it's probably a a vaulted skull, and probably not a big problem. I've seen some people say it's not a problem at all, and other people say it is a problem because a vaulted skull is weaker at the top, and the odd shape is bad for the chicken's brain. I don't have enough personal knowledge to say whether it is harmful, but I've dissected a few vaulted-skull chickens and they really did have a thin/weak area of skull at the top of the bulge, different than normal chickens.