chicapee
Songster
Candling is the sure way to know, but during lockdown candling isn't advised. Can you, yes, it's your hatch. The humidity is most important while they are pipping and hatching. I personally try not to candle until they are late or most everyone else has hatched, but a hatcher has to find what is comfortable for them. If you do, you are looking for a triangular shadow in the air cell. (The beak.) The other way you know if a chick has internally pipped is if you hear chirping inside the shell.
my chicks are a bit small so I think they are behind in development. I think my temp was half a degree low and we lost power in the night during a storm last week not sure for how long. They have been still growing since the power outage.