Some frogs do tend to eat more than others. Pickles may just be really hungry.As long as Pepper is eating and pooping I wouldn't worry about it. You can try feeding with a small cricket bowl near where Pepper sleeps so when he wakes up he will see them. I would definately not remove them for feeding as that usually puts added stress on the frog and then they definately won't eat. Why don't you post a picture of your frogs and their enclosure so we can see how you have everything set up. Also post your temps and humidity. This way we can give you better advice. Frogs do have a period of time which we call the breaking in process. They are getting use to their environment and the routine. As long as you are meeting their needs, they have plenty of hiding spots, then they will be just fine. Also girl frogs do tend to grown much faster than the boys if they are juvies. 18 days is a pretty quick growth spurt but you didn't mention how big your frogs were when you got them. Take measurments of them if you can as they are sleeping.