Are these ball pythons we are talking about? You didn't mention it in the post. Some snakes will only take fish or lizards for their first meal. If these are ball pythons you can try mice or rats, I'd try medium sized mice, all my snakes prefer mice over rats when they get picky. If the snakes are striking out of anger you may be pushing them too hard, personally I'd offer rodents every 2-3 days and just for 30 seconds or so. Don't chase the snake around with the rodent or they can get scared / defensive of it. I'll usually just hang it by the tail about an inch from their nose for about 20 - 30 seconds and then give up, usually no longer than a minute or so.

So it's illegal to have live rats? Where do you live? I couldn't imagine not having my breeder rat colony. I've found the easiest thing for picky ball python baby snakes is to put a rat pup in with them overnight, they almost always will eat live rat pups. And it would be really easy to feed dozens of hatchlings that way.