Hi Seppe, welcome to the forum. Your English is fine, I understand everything you're saying. We have several Dutch members here, so you're in good company.

I'm sorry to hear that your baby snakes are dying. Please refer firstly to our general care sheet for advice on Thamnophis care.
http://www.thamnophis.com/caresheets...ake_Care_Sheet
Some of our members are keeping Ribbon Snakes (T. sauritus) and they will be better qualified than I to give you specific advice. However, it seems to me that the time has come to force-feed the babies before any more die. You've come to the right place for help and friendly advice, please be patient and wait for replies to come in, I'm sure our members will be able to help you. Welcome again, and good luck.