It sounds like the crickets are too big unless your babies are much larger than mine. My 3 RETF babies were about 3/4 long when they came and I have been feeding them on 1 week crix and Hydei fruit flies (although now the FF are more for exercise than food). They are now 1.25" long. I have them in a 7.5 gal clear plastic tub and they are very active and cover the whole tank and just about finish everything every night. The rule is the length of the crix needs to be shorter than the distance between the eyes but not too tiny or they will be ignored. Good luck!