I'll answer since I'm here at the moment
And I I've learned much what I know about hatching from WV.
It's really up to you how much you want to candle. The candleing itself does not hurt a thing. In duck eggs I've been able to see development as early as 3 days. .it's pretty cool to see the little heartbeats during those early stages.
The risks are. .human error. . you could drop an egg. . or drop your flashlight on one.I've done that.
Or forget to put one back in the incubator. .done that too.
It's also possible you could introduce bacteria into your incubator. It's best to wash your hands and/or use gloves. . I don't use gloves anymore but I used to.
It does fluctuate your humidity and temp every time you open the bator. That part sort of depends on your incubator and how fast it warms back up and how hard it is to keep the humidity where you want it.
Too much turning is also a possible reason for mal positions, so you want to be somewhat careful about that also.
Some folks will say opening your incubator during lock down will ruin your entire hatch. But those of us who hatch call ducks throw caution to the wind and do it anyway watching for internal pips so we can track time in case assistance is needed. . which it is often is with calls.
Candleing is my favorite part of incubating. However, I do not do it as often as I did in the beginning. I haven't noticed a marked difference either way so far. So. . I say candle away if you please.
Just be reasonable about it.
I try to mostly candle without picking them up, unless I need to check the egg more carefully. And I also try to keep the egg in basically the same position and move the light around the egg, instead of rotating the egg. Just personal preference.
No pips for me yet but a bunch of my eggs have drawn down a lot this morning.
