I've borrowed a still-air Hovabator to try my very first hatch. I've done a bit of reading on here, and had thought that these incubators draw fresh air from the bottom and vent out the top. This incubator has only two vent plugs, - both in the top. The instruction booklet suggests having both plugs in for the first 3 days of incubation, which would provide no fresh air at all. Is this really a good idea? After 3 days, it says to pull the back plug, and only to pull the front plug if the windows fog up. The instructions also say to operate the incubator at 99 1/2 degrees. I had read that I should aim for that temperature at the bottom of the eggs, and 101 at the top. Would this be different if there is no air coming in from the bottom? Are all still air hovabators like this, or is this one really an antique? I'd like to get my hatch underway later this month. I really appreciate any advice!