This is my first time incubating, but from my research, it is fine to incubate no fan - but it is harder to regulate the temp. Look up "still air incubation" since that's what you'd be doing. The temps for that are a little warmer. I have a still air LG incubator, but I opted to put a PC fan in it to help keep the temperature even, which makes it a "forced air" incubator. HTH Good luck!