Works great keep the styrofoam on the bottom it helps hold heat.
I had eggs that had gotten cold over night due to a disturbed broody hen and only lost one egg and all the extras I put in hatched 3 days after the rescue eggs.

This is my preliminary review (I will post a final one after the eggs (hopefully) hatch). This incubator is going into an elementary science classroom, and the children are very excited to try this. The actual unit is well made and seems sturdy, with easy-to-follow instructions. A local farmer is providing a dozen fertilized chicken eggs, and the students will be learning about how chicks develop in the shell. So, more later!

I love my egg incubator, this is a great product at a good price. My daughter loves it too, her favorite part is waiting for the eggs to hatch. I'd like to buy another one if I have the chance.