Which slave slot are you using? If not slot 2 try this save
https://f95zone.to/threads/elf-sex-farm-v1-50-rs.135026/post-9356501
If in this save there is still not working converter it is probably some problem with the game itself.
All you need to do is to place water and food for animal and use grass on grass - food converter and it will produce food. place food to animal food feeders and that's all, but you need grass in big quantity for it and more if you have pigs, because you need to kill animals for meat. For cows you need big food feeder.