White ring around beak

[kpbchicks]

Hi -- I have a 6-month old Black Australorp that has been sick for about 6 weeks (lethargic, not eating, not pooping). She seems to be recovering a little bit (i.e., eating small amounts, flapping when I pick her up, opening her eyes more often, pooping, but watery). I noticed this morning that there is a thick white line around her beak -- at the feather line (doesn't look like mucous). Does anyone have any experience with this? And if yes, any suggestions? Thank you!