50-60 sounds like a good range.

Two weeks without eating isn't a good sign. Maybe it's stress, an illness, the temperature, (or depending on how dry they actually are), dehydration. But 50-60 doesn't sound too bad though. If they've had fresh water in their bowl before and they went to soak in it daily they might not be too badly off.

It might be helpful for them to see familiar food, but the locusts should look familiar enough to eat.