Have you had them very long? Are they pretty young? Pretty much all of mine will eat in any stage of shed. It's just the hatchlings that give me grief because they don't have it figured out yet. Have you attempted feeding in shed before? I'm asking because many new people think they won't eat in shed because they read it somewhere or someone told them that. Most BPs will eat in shed, it's a myth that it's bad for them or that none/few of them will eat in shed.

The time between the blue phase and shedding can vary, but I believe it's right around a week.