Large toe on guinea photo

[kayc]

 

[Eggcessive]

That looks like it has been injured or infected. Staph infection can be common around the toes and feet. I would look at the leg and examine for swollen joints or pain. Penicillin injections are good for staph infections. Maybe try some very warm epsom salt soaks twice a day, then dry the leg and foot thoroughly, and apply some neosporin ointment to the toe.