My chicken has a floppy dark comb and I think has bumble foot

I noticed my chicken today acting sickly. Sitting the nest box most of the day. When I picked her up (which she never lets me do) I looked at her feet and she's got a black spot on both feet. Just look at her again and notice her comb floppier than usual and pretty dark. I've ready about the bumble foot thing and I'm ready to treat her but don't know what to do about her comb. Checked her bottom. Doesn't look like she has any mites or bugs. She just had quit a bit of poop stuck to her which I cleaned off. Any advice?