Hatching or incubator?

[Prosperousity]

Hi Im a beginner to hatching! I wanted peafowl eggs for a while now and finally have a chance to get some.... But my duck has also just made a nest and were letting her hatch.
She has 8 eggs and is still laying (going to check-laid number 8 yesterday) but was on the nest a full day yesterday. I wanna add peafowl eggs if its not too late...
and if so how many more could i add to a nest of 8? She is a runner duck.
And if I cant add or shouldnt. I have a homemade styrafoam incubator but i cant get the temperature to stay sturdy when the rooms temperature rises or something. How could I fix that? Thanks!

 

[blucoondawg]

put your incubator in the basement if you have one, basements usually hold a pretty steady temperature