Hi,
I hate to have to ask this but first I guess I should ask, are these true Ameraucanas or EE's?
Having said that, I'm not sure one can make a generalization about hatching with regard to any breed.
I have hatched out more Ameraucanas than I could count right now and have had NO problems with them hatching at all.
In fact, my Ameraucanas seem to be stronger than the Welsummers and Barnevelders I've hatched this year and many of my hatching egg customers have told me they were surprised - even amazed - by how strong my Ameraucana chicks were compared to others that were hatching at same time.
Just FYI, I recently hatched out about 50 some Ameraucanas and Welsummers. I had two power outages, for about 2 hours each time, during the time the eggs were in my Sportsman. They were supposed to hatch last Saturday. Three Ameraucanas hatched on Friday night and no Welsummers. All of the Ameraucanas hatched on Saturday and most of the Welsummers but some of the Wellies didn't hatch until late Sunday night.
Finally, I never mess with the humidity. I keep it the same all the way from beginning to end.
God Bless,