Question about what I think might be pasty butt

[Tremogg]

When cleaning my chicks enclosure today I inspected their behinds and did not see any severe or obvious pasty butt. But I did see a few with little lines on their fluff and one that has a little bit of red around her up in the fluff. Is this pasty butt?

 

[Wyorp Rock]

Here's a good article along with photos that you may find helpful.
https://the-chicken-chick.com/pasty-butt-in-chicks-causestreatmen/