It is only a 40 watt, and it is on a dimmer. I have other eggs in there, so I am trying to keep the overall temp near 100.
I have hatched chicks in my incubator twice, the first started pipping at day 18, with 5 pips, all the chicks were hatched by the end of day 19, except for one. The second set, I also had a hen setting, due the same day, and the eggs in the bator, as well as the hen's eggs, were all hatched by day 20. I even had one that was hatched completely by the end of day 18. These eggs have been set by a hen the whole time. I did add a few (like 4 or 5) eggs to her nest, cause she only had 2 eggs, that were from the incubator, but they had only been in the bator for 1 day. I have 5 hens that have chicks, and out of all those, only one of them had her eggs hatch on time, and she was setting on a mix of RIR, SLW, and leghorns that my dad had gathered from his hen house.
I was just concerned that the hen would not take the chick. We had a hen hatch the other day, and she left the nest with eggs still in it. We brought the eggs in, and 2 were pipped. One of the chicks took a while to hatch, and was only about 6 hours old when we gave it to the hen. We ended up having to bring it back in the next day, because it was just laying on the ground, and the hen would not let it near the others. After a day to get it's footing, we took it back out last night, and there have been no problems with it since.
But you are right, poulets, that it is the norm here that my eggs hatch early. I only have one roo right now that is old enough to do the job, and I wonder if it is something to do with his genes. Everyone of his chicks has hatched early, except a very small few.