Look at these chickens go! They absolutely love sunflowers. 

Chickens will peck sunflower seeds right out of the head. Since the seeds consist of 26.3% protein, they make a great addition to a chicken diet.

In the fall, we cut them and hang them to dry, and then, through the winter, when the chickens don't have much else to do, and they might be prone to start pecking each other from boredom, I hang them just up above head height, so they have to stretch to peck them, and they swing a bit. The seeds fall out and they all run them down, and then start again with another peck. Gives them something to do.