Coturnix quail hatched with black patches on feet?

The little guy pricked a vein when he pipped and once he finally hatched his feet had black patches like little bruises on him. Has anyone seen this before? Google and search turned up nothing.

 

Anyone? He looks otherwise completely healthy and his feet seem to function just fine.

 

Thanks, these are my first quails and he was the only one like this. I was worried he had injured himself.