I try not to be obsessive about counting my chickens. But I do try to count them every evening when I'm locking them up.
The other evening I was one short. One chicken had been outside the fencing during the day so I figured it was that one. In the evening when they're roosting or settling down, it's almost impossible to see the different breeds. It wasn't until the next morning that I could tell one of the brown Americanas was missing.
Sometimes you never know what happens to them. When they get outside the fencing, you can't protect them.
But at least this time I found it. I found it lying dead on the driveway. I think Lilly either chased or "herded" it until it died, or maybe something else killed it and Lilly carried it around to the driveway.
This leaves us with 22 chickens: 21 hens and one rooster. The hens are all beginning to lay again and I'm getting about a dozen a day.