Come to think of it, foal blankets really are not that hard. A few years back we had an EMU that the goat ate all her feathers so she was quite bald. I went out with a tape measure and took a few measurements and came in and drew it on a paper sack. this was a bit tricky because she needed a very small neck opening and from her neck to her tail she had a hump in the middle of her back that had to be accounted for. My first ruff draft didn't work. I was making the outer shell out of twill with a lining of polar fleece. I had just made the outer shell and tried it on her. I came back in. Made it a bit bigger and actually used the outer shell as the pattern for the lining. She loved her blanket but did enjoy the days she didn't wear it. It was really hard to part with her blanket when she passed. Anyway, you measure length front to back. How large you need the neck opening. Then you need to know the drop from the shoulder and top of the butt down the side. Easy as pie.