I spoke to my brother last night. He told me that a vulpine intrusion had accounted for two of his hens.
It seems that these hens, which he had only a couple of months, flatly refuse to go into the hen house to roost at night. They go in during the day to lay their eggs. Brother David said that their pen is entirely enclosed in wire netting but Mr. Fox found a weak point and forced his way in. He killed two (half the flock) and carried one of those two away.