there are lots. o chickens without otter toes. feathered legs are common to have rudimentary toes. I have have had a few in my Marans. it will be fine.
I have a MF Leghorn that lost its foot...it has never figured out how to walk I need to cull it but it is a MFL......I need it. but I think it has to be done.
How much of his leg is left? I bet that I could make him a prosthetic that would work if he has enough of a stump to affix it. I think with using bamboo and silicon calking to cushion between the stump and the bamboo would work. The trick would be to fasten it in a way that doesn't restrict blood flow. That I would have to see the amputation to figure out. It might not work for the long term but if it can restore him enough for a breeding season then you can hatch his replacement.
I am currently working with a kitten that got slammed in a door (in the dark) that I had to amputate one foot and the toes from the other foot. He is still not healed so it is too soon to make his prosthetic. I had a goat that jumped a fence in the storm and caught his foot in the fence and ruined it and I had to have the vet amputate the leg at the hock. I worked out how to use rattan and silicon to give him a prosthetic. But before I could implement the idea he got in a shoving match with his buddy Abram the ram and was cast upside down and couldn't rise without the missing foot. I rescued him before he died but it was too late he had been upside down too long. (That will cause the circulation to fail in the four stomachs and organs and cause tissue death.)
PM me if you want to try. I am over in Goodlettsville/Millersville.