You don't have to open the incubater to mess around with unhatched eggs or the shells. Just take out one of the red plugs for the top vent, get yourself some long wooden skewers ( like for the BBQ) and reach in through the hole. I learned this from my 10 year old MMR daughter. Cought her in the act after I threatened her life if she opened the incubater. She also used the eraser end of a pencil. Brilliant!! Now I just have to make sure she's not around to catch me in the act!!
