It might be a good idea to get two different sizes. There were a couple of times I needed a smaller one than what I had. It's best to get that bumble foot taken care of as soon as possible, before it gets huge and waay u comfortable.
This stuff is cheap, works great, and easy to apply. Great for mites on their skin too. I spray under their tummy, on the bottom, under wings, neck, behind neck. Easy to do, easy on them.
That's pretty darn swollen for mites, but if so, I always used something that folks can't believe works..but oh boy does it! I buy the lice spray from a pet shop .says for canaries..works great on chickens too.. imagine that!
Have the above things ready. Put chicken under towel..head covered. I soaked their feet in warm water with epsom salt in it. The scab becomes soft. I take the puncher..punch into the middle of scab. This girl had a big one line yours. It took a lot to get the plug out. That white stuff stays...