Spots on Tail Feathers - Parasites?

[rm09boug]

Hello folks! I noticed a couple of my hens have these dark spots on their tail feathers (pics below). I recall from my studies of avian parasites that this could be frass from mites or lice, but upon inspecting their vents/necks/wings and their coop, I cannot find any other signs of pests. Is there anything else that could cause his discoloration or should I start treatment anyway?

Thanks for reading!

 

[nchls school]

Have you looked at this with a magnifying glass? You checked the hens or parasites so don't worry about it. Could be residual dirt from dust bathing.

 

[rm09boug]

Thanks for the response! I was wondering if a little mud or dirt could make the same discoloration. It’s been so wet lately due to snow melt that I wouldn’t be surprised!