I've had 3 silkie chickens for 3 years now. I have always let them out into a chicken yard 2-3 days a week. The other day I was called away and didn't get home until about 10:30 pm. I closed the run door as usual and went to bed. When I went out the next morning, one of the chickens was out in the yard (alive and fine), another was sitting in the corner of the run (alive and scared) and the last one was in the coop (her broody sitting spot) missing her head and neck. There was no blood. I guessed it was a possum. Thank goodness it had left prior to me closing the door and thankfully it wasn't a dog or a raccoon, because I would have had 3 dead chickens instead of just one. I set out my trap and caught a big fat possum. He is now going to fertilize my plum tree. I live in the city. My coop is inside a 6 foot fence. My coop and runs are enclosed in hardware cloth. The perimeter of my coop and runs are also encased in hardware cloth. I have been late closing the run door many times in the past and there has never been a problem. I knew chickens bring in predators. I have read the heartache stories. I have seen hawks flying around but have always gotten my chicks back in the run without mishap. Sadly, now I really know chickens bring in predators, even in the middle of a neighborhood in the city. Even when you think you have built Fort Knox for your girls, they are still at risk if you let them play in the yard. I also learned I can handle the loss. I didn't cry or get overly angry at myself. Thankfully it's not like losing a dog (for me anyway). I think I'm going to get 2 more silkie pullets in the spring. I'm still going to let them out in the yard some. They seem to enjoy it so much and I enjoy watching them come running when I call for them. But I dang sure will put them up before dark. And I think I will set up my trap every few months just to catch anything coming around that might be a danger to them.