And then there were three

Rest in peace white chick, we hardly knew ye

Sad sad news, the white chick disappeared during the night. Late at night we checked on them and she was in, and first thing in the morning she was not.
It was raining constantly so I could not tell what had happened, but I guess one of the neighbor cats managed to sneak in through the fence bottom part and caught and ran away with her.  Either that or she found a small hole and escaped in which case I assume it is just a matter of time before she gets either eaten by a predator or hit by train. So very unfortunate...
Any blood trace was washed away by the rain, but I saw quite a few white feathers outside the back of the coop and also a few on the other side of the JR fence. The track of feathers led into the thick grass and bushes. I didn't find evidence of struggle inside the coop so if there was any predator it must have caught the white chick while she was outside...
I bought some wire fencing for the bottom part of the run fence and attached it. Now it is really tough to get in or out. (In the remote chance of the white chick still being alive and somehow coming back, there are still openings outside of the run leading to the garden)
Also I had left the coop door open all night but from now on I will close the coop door during the night time when they are sleeping anyway.
The remaining 3 seemed a bit scared at first but now after I fed them lots of treats and bugs they are out and have really gotten used to me. They come close to me even when I have no treats for them.
I feel very sad for the white one though, I should have been more careful. Sorry girl...