Ok I have a 2362 Hovabator with both chicken and duck eggs in right now and I want to get a hatcher - this is just my second set of eggs- I didnt want to spend much $ - does the hatcher need to have a fan? Dont have time to make my own
Ironically, a hatcher probably could use fan more than the main incubator.
Once the conditions inside a still air incubator are stable, it's not too hard to keep them there. With the exception of changes in ambient conditions, there are no major factors influencing the internal temp and humidity.
In a hatcher, the eggs are in their last three days. The embryos are large, moving, and generate significant amounts of heat. Once they pip they also add to the humidity (often no bad thing).
The excess heat isn't very easy for most cheaper incubators to deal with, and there is a danger they could get too warm.
If I were using a hatcher like this, I would probably start day 18 with the temperature set 1F lower than the incubator, and keep a very close eye on it.