I heard somewhere dirty back feathers are a cause for concern? Now my bird has them...

[alexis187]

One of my chickens has a pale comb and suddenly messy back feathers...should I be worried? Pics attached

 

[Wyorp Rock]

Give her a clean up. Check for lice/mites, crop emptying overnight and observe to see if the bum keeps getting messy like that. If it does, then photos of poop would be good.