ISA Brown dead

Something attacked chickens while we were at dinner - still light out when we came home. Must have been non-flying predator, 'cause 3 of the girls were sitting up on top of my load of mulch. There were ISA Brown feathers everywhere, no signs of the carcass. My BR was MIA - found here this morning under our deck with tail feathers gone, in shock. I don't see any blood on her, but she sure isn't moving like she used to. Do you think coon or coyote would come out when still light out? We got home around 9pm. I still haven't ruled out our neighbors dogs. They just all turned 18 weeks last week and I had just gotten some eggs (i'm pretty sure from the one dead and likely from the one in shock).