Rooster limping- need to make cast/crutch

[Minky]

He is about a year old. He is a large Black Copper Maran, and was in a pen with two other Marans roosters. They are very gentle, and so I don't think it was a fight. There was no blood, feathers etc... I noticed him limping about 2 weeks ago. I waited 2 days, but seemed to get worse and the roost is about 4 feet off the ground, so I removed him and put him on his own in a small hospital cage. One week later, he is now not putting ANY weight on it and is standing on one leg all day. I have inspected him thoroughly three or four times, but not being a vet, and knowing little about chickens... I dont know what to look for. His toes are open and flat when he holds his leg up. I've checked for bumble foot- the pads of his feet look good. He doesn't seem to ever grab my fingers with those toes, but the leg doesnt seem to be broken or out of its socket.
I was going to make a cast/crutch. But really have no idea how to help him.
I need this rooster.

Can someone offer ideas?

 

[Eggcessive]

A splint won’t help if his leg is not broken. If it is broken, the location of the fracture would affect where the splint is used. The area above and below a fracture should be splinted. Some problems can be in the hip, long bones, or the foot. Do you have pictures of his leg? Could you get an xray of the leg? I would look for any swelling, redness, green bruising, or small cuts over the entire leg up into the feathered part to the hip. Here is a good pic of the leg bones:
https://www.dummies.com/wp-content/uploads/369894.image0.jpg