That is what I thought when you posted about loosing your roo, 'The dog did it', no one likes to hear that news. Sorry about that,
I hope some of the dog owners here can give you some tips on how to break him from killing your birds.
I tried to post this little story a few days ago but when I hit send it disappeared.
I will try again.
A few days ago before Prairie Fleur lost her roo, Okie Queen Bee and I noticed the birds making a racket, we went to the window and watched a hawk dive to the ground beyond our coop. The older guineas took after it and the hawk flew to a near by fence post where it sat for a few minutes as the guineas squawked at it. The hawk decided that it should reclaim it's kill and flew back to the point where it had landed before only to have the guineas chase it again. This time it sat on the fence post quite a while before getting annoyed by the guineas and flew off leaving the area. We suspect that it had killed a mouse or rat and the guineas took it from it and kept it for themselves. Hopefully next time it will take a guinea instead, they are vile creatures and need thinned out anyway.
We raised some white ones for owl bait, I am hoping that the owl will take them instead of our free ranging turkeys or peafowl.