Do you already have the chickens? We favored the heavy layers like orpingtongs, cochins, & australorps because they didn't like to fly over barriers. We could keep them out of the garden with a 2 foot fence and the 4' high post and rail fence was an insurmountable barrier to them. Banties can fly across the yard and land in the top of a tree - no containing them!
I think for grapes you'd want a heavy gauge wire because the weight and pulling to get off old canes when you prune will bend a lesser wire. You may want an inner fence to keep the animals away from the grapes. Hens will scratch away any mulch you try to use, and help themselves to the grapes they can reach. Goats would strip the leaves from your grape vines before you know it. On the other hand, hens will also eat the japanese beetles they can reach off of your vines, and my grapes did fine with no mulch under them. The hens liked the shade and beetles and I think deposited plenty of manure around the grapes. If you get a small pig, you can make a portable pen of hog panels to keep it where you want.
We thwarted our hens from landing on the
wood gate to fly into the garden by running a taut string or wire a few inches above the top of the gate - they like to land on a solid surface and that string wobbled and tangled their feet.