Depending on how big the snake is, you might want to try FFing tail segments rather than whole pinkies (or whatever size). I haven't had to to this with a ball python, but one of our green trees refused to eat when it was younger and after 8 weeks of no feeding I started feeding 1-2" sections of rat tails that were taken of my RTBs rats and now he eats like a pig.

I tried FFing full pinkies but they're just too "mushy" and I couldn't get a good angle to get them to swallow it, but the rat tails kinda just slide right down and they're better than nothing. Just keep in mind to go from the big end to the small end to go along with the hair.