I've found crickets are surprisingly good at hiding in tanks. You can try using a tall, smooth bowl with steep sides to put the crickets in. That way you can tell if any are missing. Also are the crickets the right size for the frogs to eat? Roughly the length from eyeball to eyeball would be a good size. Juveniles should probably be fed more frequently than adults too.

You might want to cover part or all of the tank to help the frogs get calmer and adjust.