18 day old pigeon lacking head feathers?

[the_finch_family]

Hello! I'm raising 2 babies right now, and the older one seems to only be sprouting a few feathers on his head while his/her sibling almost has a full head. Is this normal? Could it be a sign of something going wrong?
They're growing well, and are very energetic, this is pretty much the only strange thing about this one.

 

[Chicken_tiger_catt]

I don't know much about them, but I think the babies just look like that.

 

[the_finch_family]

I don't know much about them, but I think the babies just look like that.

I'd think it's normal, but his 1 day younger sibling already has his head feathers coming in at once