Last night I put my chickens away and I counted everyone, all 17 of them, as I put them in their 12x12 secured coop. This morning I went to let my hens out and my leghorns were eating my batman frizzled hen. They had food and water. The frizzled hen wasn't sick or injured last night. So I'm unsure what caused this and how do I stop it? This is the 2nd time it has happened this week.