After this incident, I researched foxes a little and what I read was that they will go on a killing spree and then bury what they can't eat immediately, to stash it for future meals. Since I interrupted him (I think) the first time, he didn't get to carry off and bury the dead birds. Two bodies I never found and I assume he carried off or ate those.
This morning there were piles of feathers from our barred rock, no sign of the other two. They are tiny little bantys and presumably gone now. DH is bummed. We have tried so hard to keep them safe, but want them to be able to free range as well. We are thinking fox as there was nothing but feathers left behind. Little bastards, we love those girls.
