The incubator doesn’t have a humidity gauge. I went to tractor supply to look for one yesterday with no luck. I put water in the bottom yesterday around 11. I will get some shelf liner today on my lunch break. Does it matter where I make the slit in the membrane?
You don't have to mark the air cell to assist - you can candle the egg and see where it is. Honestly now that it's zipping you really don't even have to do that, it's more of a 'just to be safe' thing. You're likely fine to just finish the zip for the chick at this point. With no way to tell what the humidity is, it's quite possible it's too dry in there and it's gotten dried out and stuck to the membrane and that's why it's not progressing.