Bump on my chicks head

[Chickie]

I had two chicks hatch last night of the same breed. One has qiute a large bump on its head. Other than that it is fine. It is walking around and seems quite strong. I'm hoping the bump just goes away. Could anyone tell me what it is or if If they have ever experienced anything like it.
Thanks

 

[Picco]

If its a crested breed (silkies, polish...) it could just be the normal skull morphology (aka the poll). It not I don't have a clue. Hope this helps.

 

[Chickie]

Hi yes you could be right. They were very small eggs and a creamy colour. Only problem is only one out of the two has it, could that mean they are a boy and a girl. It is very strong and it picks one the other a bit, it is also very noisy.
I would add a picture but not sure how too.

 

[silkiechicken]

It probally just means one will have a nice crest and the other won't... hope for hens!