Yes, it's bumblefoot. It's good you noticed it so it can be treated. It begins with a bruise from a harsh landing getting down from a high perch with not enough cushioning underneath. Or it can begin with an abrasion or cut or a splinter. Bacteria, usually staph, enters and begins to form a pus plug that can get larger and deeper if treatment isn't undertaken.
Treatment is simple. Soak in warm Epsom salt water fifteen to twenty minutes to soften the scab. Then scrape it from the foot with a thumbnail, careful to lift out any pus "plug" with the scab. If there's no plug, you're lucky it hasn't become infected yet.
I spray the cleaned out wound with Vetericyn, let dry, and squirt on some triple antibiotic ointment and bandage well to keep out the dirt. I use a non-stick gauze pad over the wound and wrap with Vetrap, cut into one-inch by twenty-inch strips, to secure it and to keep it clean.
The chicken may be released back into the flock while it heals. In a couple days, unwrap and inspect the wound. If it's healing, re-bandage and inspect in another five days. If the healing is far enough along, you may be able to leave the bandage off.
There is a chance this will be a more serious infection. You'll know by the depth of the pus plug. It could require weeks more of soaks and bandaging. I had a case that required two years of treatment. Most heal in just a week or two.
