Are these coturnix quail male or female? They're losing feathers!

[Eloise Marie]

Hi,
We have 4 six-week old coturnix quail that I was pretty sure were male, but yesterday when my brother and I went out to check on them two of them were missing their head feathers and another one looked like it may have lost a few, but not too many.
If you all could just give me your opinion on whether they're male or female and what's going on with the feathers that would be great!

 

[Nabiki]

Males will mount other males if nothing else is available. Are they crowing?
The 6th picture looks like a male to me from the brown on his head, but the others aren't easily sexed by feather pattern.

 

[Eloise Marie]

Thank you so much.
I thought they were, but after looking up quail crows, I'm pretty sure it's just more of a loud cheep.