It was easy IMO. I used a saber saw (it's electric not a hand saw though). You just need to drill some holes first with a drill bit big enough to make a hole that the blade of the saber saw can fit through in order to start cutting with the saber saw. Also, make sure the blade is a metal cutting blade and not a wood cutting one. I should also note a lot of people just leave the door the way it is. You just have to open the door to check on the eggs that way as opposed to looking through the window. But even looking through the plexi glass window does not give you a clear view of all the eggs through the steralite tubs. I just like the ability to be able to see whats going on in there (the best I can) at all times without having to open the doors a lot.