I might be wrong, but I would try everything. Maybe try hand feeding, if they do not run away. I just bought some plastic tweezers to get one of my new girls to eat worms, I’ll let you know if they work. Try crickets, if they do not work, take them out after 15 minutes and try the next day. Leave some mealworms out in an escape proof container 24/7, make sure they are visible. Count them to see if any are missing. If you can afford it, try some other types of worms, butterworms, silkworms, waxworms, but do not get them hooked on these guys. One of my new leos won’t eat unless she can't see me and it is dark.
If they are just baby leos then they have not developed enough fat reserves in their tails to last very long (well not as long as an adult). I wouldn't worry if they don't eat for a week, but keep trying, without disturbing them to much. For example, are you taking them out of their hides to feed them? if so don't. Try once at day at the maximum. If I see my little guys out on the prowl, I know it's dinner time and their hungry. After a week and a half to two weeks I personally would get nervous and at least call a vet. Did you get them from a reputable breeder? if not you could take them in for check up anyways. They could just rule out any sort of parasite... If they are from a reputable breeder I'm pretty sure that they will come around.
This is just my opinion, based on things I have been told and experiences I have gone though.
Lisa
-----
0.1 Hypo Leopard Gecko
0.1 Albino Leopard Gecko
0.1 Blizzard Leopard Gecko
1.0 Pacman Frog (Phatty)
1.0 Lovebird (Tony Montana)
1.0 Elkhound (Otto)
0.1 Malamute (Paris)
5.0 Bettas