I have planted sunflowers In my gardens here at the house every year. This year is the first time I have actually had flowers. The deer would eat them every time while still young plants. This year I put up some ‘trip’ string ( Strong fishing line) with tin cans on each end. It has worked great. I guess it startles them enough that the go elsewhere. The birds are harvesting the seed heads now.My brother can’t keep deer or pigs out of his garden each year, and he has a 5 or 6 wire hot wire that I think is 8’ tall at the top wire.