My aunt and uncle have plenty of grapes on their property, and dogs, and neighbor dogs that run through regularly. They've never had any problems, and it's been this way for decades. I don't know if that's unusual or not, but I've never seen any of the dogs eating the grapes.
I have vinca major and wisteria vines in my backyard, I hadn't thought about them potentially being toxic to chickens. I guess I assumed that chickens wouldn't eat something toxic. Are they likely to be a problem?
Both of those vines are lovely though. I don't know how they would do in your zone, but out here (zone 9a/14) they will take over anything that sit still for too long. I would never plant vinca major in the ground, ever. Too hard to eradicate. Out there it might be an annual though.