I have had an automatic door for almost 3 years after 22 years without one. Only had about 3 times that it locked chickens out. I check it every night, so the comments about not checking are not applicable. I bought it because I go away about 10 times a year & previously they were left open the whole 2-4 days I was away. Love the auto door. Don't know what door the OP actually has. Mine is the Advanced Automatic Chicken Door from Fleming with a homemade plywood door weighing about 4 pounds. It does close slowly & I am baffled as to how a hen would allow herself to be caught under it. Must have been a freak accident. Sorry for your loss!