So with our last clutch, for the first time we had to deal with a umbilical cord that was knotted. We were lucky that the baby came out of his egg with him umbilical still attached, so we could see the problem.

Do breeders check for twisted umbilicus while the hatchlings are still in the egg?

For instance in that same clutch, we had a Bumble Bee that didn't even pip. We left it alone and it died. We didn't check why it wasn't even sticking his head out. In situations such as this, do breeders intervene, or just let nature run its course? I'm not even sure how to go about checking for a twisted umbilicus without disturbing the hatchling/removing it from its egg.