I would say each egg isn't the same. Different location in the incubator and possibly one egg was better material to incubate then the other. Did that make sense? I've had that happen too.Question for you all:
How do I get 1 chick that hatches out fine, fluffs and dries out perfectly within a few hours. Then have another chick that hatches out minutes after the first one and is very wet but when it drys out is so sticky that it actually acted like glue and the poor thing was stuck to the hardware cloth and couldn't move? I dry incubated from day 1-18 (low 30's) and then upped it to 65% for lockdown.