I would not take a chicken with bumblefoot. It is an abscess which forms after a cut on the bottom of the foot becomes infected, so it is technically not contagious, but the bacteria involved is usually one of several difficult to treat ones, such as Staphylococcus aureus. You don't want those kinds of bacteria around if you don't already have them. Also, the abscess can be very difficult to treat, and recurrence is common.
If you do decide to take the chicken, there are non-surgical alternatives I would try first, since the surgery is done without an anesthetic and therefore quite painful. If it is mild (not red, not hardened, and not so swollen that bumblefoot is obvious from looking at the top of the foot), then there is a good chance you can soak it out with epsom salts or TricideNeo. I have used the latter twice now, with success, though others say it did not work for them. Someone who has treated a lot of hens with bumblefoot recently says it works about 70% of them time.
