Hello everyone! New to the forum (and to frog care).

In June, I received 6 grey tree frog tadpoles, which I raised. They morphed around July, and there's been a huge difference between the frogs ever since. Two were large and round, stayed visible during the day, and tolerated my hand without problems. Four hid constantly and were small. I fed fruit flies at first, but it soon came time to try crickets. At first, only the two already-round ones would take them from me. Soon, however, two more brave frogs joined them, and now they're still smaller-- but nice and round. They also stay visible during the day, and not only tolerate-- but seek-- my hand. Sometimes they ride the large tweezers after they grab a meal!

The problem is that the two hold-outs are not only staying small and afraid of me, they're becoming skeletal. Yes, I'm providing fruit flies-- tons of them-- every night to make up for them not eating crickets. Problem is, I don't even know if they're eating THAT. What could the problem be? And what do I do about it? I see people talking about force feeding, but I can't imagine doing that to these tiny little guys. Is this normal? Will they eventually come around, or is this an indication that something is wrong with them?

It's really too bad because one of them has exceptionally beautiful coloration-- very pale grey with black lines coming from the eyes and larger, darker eyes than the others.