If you have a basement that stays cool or a small fridge kicking around you can keep worms for the winter, Stefan. (well, at least most of the winter- I'm sure they are longer where you are than here!) I go outside for the last week or so before it freezes, and catch as many nightcrawlers as I can get my hands on. Then I throw them all in buckets of dirt, and keep them in the corner of the basement where it stays fairly cool. Just make sure to keep the dirt wet and top it up with unfertilized potting soil every couple weeks. Most of the worms live through the winter and a picky eater snake is still happy!! I understand the nutrition is not topnotch with this diet, but while you work on persuading the snake to eat other things it at least keeps her fat and happy