I don't deworm, I haven't had a reason to yet for the past 2 years. My flock is very well maintained and cared for. Their very spoiledWow! I'm glad to hear your having such amazing hatch rates. I'd be thrilled with 90%. I personally feel health of the flock is the #1 predictor of a successful hatch. You can almost anything to those eggs and they hatch. If you have even a marginally maintained flock then your incubating need to be spot on to compensate.
By well maintained mean healthy young adults, ideal hen/roo ratio, dewormed on a schedule, allowed access to foraging, free choice high quality layer feed, and sanitary conditions in the runs and nest boxes.

My birds are pretty much cared for the same as my dogs and cat. I even go outside and sit with them and talk to them

This is my prized possession. He's a Black Jersey Giant. He's the father of some of the chicks. I just love the way he looks and he's so massive.