Not a single one hatched The only differences that I noticed were that the humidity was higher in the beginning than it usually is. I do a dry hatch until lockdown, but we had so much humidity in the air that it was in the 30% and occasionally made it to 40% (with no water added). The other difference is that we had a few hot days in the middle of the hatch ( in the 80's & high 80's outside) which drove the temps up in the house & in the incubator ( but I never saw the incubator go above 102 - 103).
I have never tried hatching by weight before, but when I weighed the eggs on day 10 some of them were already at 12% weight loss, so I am wondering if the chicks didn't have enough room to turn around & get in position. I never saw any of these eggs wiggle & never heard any of them chirp. I left them in the bator for 4 extra days, just in case, but nothing hatched. I still need to do my egg topsies to see if that helps me figure anything out.
What bator are you using?