I agree with the other posters. The poor thing could just be sad and lonely, as any of us would be following the death of a friend. Before assuming she's sick -- which could, of course, be true -- so long as her condition isn't worsening, the first thing I'd do would be to try to get her some friends.
Does she have favorite comfort food? Maybe if you invested in something like a jar of live mealworms from Petco -- no healthy chicken can resist! -- and fed her a few at one or two structured times of the day, it would give her something to focus on & look forward to every day. Just a random thought...
Does she have favorite comfort food? Maybe if you invested in something like a jar of live mealworms from Petco -- no healthy chicken can resist! -- and fed her a few at one or two structured times of the day, it would give her something to focus on & look forward to every day. Just a random thought...