Can anybody tell me about skin rings on feathers?

[Careta]

Hello everyone,

My darling little cochin has skin rings partly down her feathers. Looks like little rubber ties
. I believe it's called the epidermal collar.

Is it normal for these rings to travel down the feather? I'm really worried because the other time I saw it was on my chicken that died.

Can anyone give me advice? She seems completely healthy otherwise

Thanks