Shhh, don't tell anyone, but I candle my eggs almost every day, even during lockdown. The air is so dry right now that I have to add more water to the reservoirs, even during lockdown, otherwise it would run out entirely. That means I have to open the incubator up anyway, so I candle while I'm at it. It helps me to make sure the air cells have reached the proper size, it tells me if any of the eggs have pipped internally, etc. So I would say sure, go ahead and candle!
This might sound dumb but can i candle my eggs on day 21??? I heard chirping on day 19 and now nothing for 2 days. They are in a dry air incubator and i have kept the temp between 98-101 but i dont have anything to measure humidity. Although I have kept the water reservoir full. Any thoughts?????