What’s wrong with my chickens foot?

[xogarb]

 

[-Kiwi-]

Looks like a popped blister of some kind from an infected wound... maybe a splinter? I would say rinse it out with some disinfect it and quarantine her in a place where dirt and grime cant get in there.

 

[coach723]

What does the bottom of the foot look like?
I would soak the foot in some warm water with betadine or chlorhexidine mixed in. Clean all that out, lance the swollen part between the toes if needed and flush everything out with chlorhexidine. Then fill and cover it with some triple antibiotic ointment, cover with a bit of telfa pad or gauze, and wrap with vetwrap or co wrap to keep it clean. Don't wrap too tight, you don't want to cut off circulation. Change the bandage daily, flush if needed and reapply the ointment and rebandage. I would do that until it's healing well (may take some time) and continue the bandage until it's healed completely.