There are no veggies high in protein that chickens love. However you could plant a large bean or pea patch. Chickens loth beans even soybeans, they must be cooked or defatted in some fashion before in most cases a chicken will eat them, defatted or fat-expelled soy for example is relished. Hens do love to pull and eat the blooms and blossoms off of pea and bean plants however so a sizable pea patch may be worth looking into. Another problem with vegetable sources of protein is the type or kind of protein it is. Chickens being a kinder gentler version of a T-Rex Dinosaur relish animal protein and it has the kinds of protein that chickens need. So don't worry too much about vegetable protein because you hens will all want to know
"Where's the meat?"
