I apologize for not responding sooner. Silence is frustrating.So if I’m candling at 17 days, how can I tell which eggs are still viable? I can’t actually see any movement...
If you gently tap the eggs, and they don’t explode, assume you’re okay. That sounds like the best option for you right now.
I’ve used sand, but not in the nest box. That sounds interesting only because it is new to me. No, you don’t have to change that. It will work fine.