I have a cabinet incubator that is the typical 3 rack one, (three trays to the rack) which hold about 2 dozen eggs in each tray. About 100 eggs in the incubator right now. There is three vents on the top and three vents on the bottom (back of incubator of course). In a previous post I have shown a picture of the incubator, but have not had any responses as to what the make or model is. A manual did not come with it when I purchased it (second hand) As I do not have the instructions to the incubator, I require some assistance with the method of which vents to have open/closed when. A quick tip on when to open/close and when this should be done would be very helpful. We are on day 12 of incubation, candled this morning and it looks good so far, only three unfertile eggs in the group. Have a great day, CynthiaM.