Smaller eggs = Faster Incubation?

I have small bantam eggs set in the bator along with regular brown eggs. I'm on day 7 right now. I can't see anything in the brown to make me think they are good. If there is no air pocket, are they bad eggs? The bantams eggs, however, I can see what looks like a little beating heart. My question is, do smaller eggs incubate faster then larger ones??? The larger eggs are easily 3 times bigger then the bantams. I would think with such a smaller surface and area to heat, it would grow a bit faster. Are the bantam eggs growing too fast?? Thanks for the help.