I have a backyard flock that are just over a year old. about two weeks ago, I noticed one of them lying on the coop floor when I went to close the coop up. All the rest were on their roosts. She was dead the next morning. Tonight, we found another dead hen on the floor of the coop; she had been out roaming the yard most of the day and then dead. I don't see any obvious signs as a cause. In the second case, no lethargy or unusual behavior beforehand. I do give fresh vegetable/fruit scraps in addition to their pellets. We have sparrows visiting in the coop, could something be transferred from wild birds if the hens are eating their feces? Not sure what to do to prevent a potential problem. Any advice is appreciated.