Make sure the producer who supplies you with starter stock raises his stock under the proper conditions. If you live close to him, go by his place and look him over. If the rearing conditions are not right, then move on to another producer. Humidity not right. Temperature and lighting incorrect.
Some stock looks suspiciously weak or ill.
Sanitation isn't up to par. After you know a little but about what you're doing, you should try to arrange a visit to the nearest producing insectary. Ask as many questions as the owner will permit. Try to see as much as you can. There's a lot of unnecessary secrecy in the producing end of this business.