Here is a link to a source of chicken saddles with wings ...
http://www.hensaver.com/FAQ.html
The one I made with nothing more than needle, thread, scissors, flat elastic, and an old pair of jeans was the very simple kind ... with tighter wing elastic, it never came off and was all cotton/breathable, didn't get too dirty, and it looks as good as new after a couple months of constant use. It was held away from the wound by the hen's feathers ... so the wound could heal.
I'd be worried about plastics or synthetics. Honestly, I'd be worries about duct tape type things. But I'm curious about using them for a saddle.
Thanks for that info! You made the simple kind am I reading that correctly? How did you measure? Across the back and around under the wings?