We have a crippled chicken, and bought his wheelchair here:
https://chickentherapychairs.weebly.com/
They are in Australia, so the shipping is expensive, but I was having a hard time figuring out how to make one, so it was worth it to me. They are super nice people, and the proceeds go to funding their farm animal sanctuary.
Our chicken outgrew his wheelchair pretty quickly (either that or I measured wrong), so I ended up copying the design and making a new one myself, with a few added improvements, like a bag to catch the poop.
The one thing I have not tried to replicate, and I'm not sure how hard it would be, is the food dishes and the metal holders, but I'm sure you could work it out or find something similar.
Our chicken likes his chair and has learned to scoot himself around on our hardwood floors. I highly recommend it.