Bumblefoot in quail is when a hard lump forms underneath the foot usually where a small wound has been.
The lump is formed when the infection is still there. Usually the quail will be limping.
If the infection is still active the foot will feel hot and swollen and can be treated with an antibiotic treatment.
If the lump is near the surface then you may want to lance the bump and squeeze out the pus and then treat with a veterinary spray.
If you do lance the lump then you may wish to keep the bird away from the other birds as the others will sometimes pick at the wound.