During the winter I put my ducks into a very sturdy 4'x8' box completly insulated and even equiped with a video camera so I can check up on them without going out into the freezing cold. Well this morning I replaced the locking mechinism to a barrel bolt placed verticly at the top of the door. When I went to put them in tonight I walked into the box and the door slammed shut behind me becuase it has a spring on it. I didnt think anything of it becuase I designed it to close behind my so there are no escaped ducks. So I went to open the door and the shock of the door hitting against the box made the barrel bolt close and lock me in. I spent almost three hours locked inside before the family realized I never came back in. I sure was thankful for the insulation, I walked outside in my pjs because it only takes me about a minute to put them in, needless to say it was still a bit chilly.