DylansMom,,higher incubation temps such as 100-100.9 will result in eggs hatching out a day or so sooner,slightly lower temps adds a day or two to hatchtime based on the 99.6 recommeneded.I very seldom have pea eggs hatch on the 28th day,,normally the 26th day they pip and are out,or by the 27th day they are out.
We have found the same to be true, almost all of ours pip on day 26 and hatch on day 27. I was just wondering about Birdrains statement that "Coco" hatched at 24 days. I've never had 1 hatch that early, although my hen hatched ones usually arrive 2-3 days before I am expecting them, but I have a theory on that.