centrarchid - Thanks again for all your advice. My husband finally agreed to build the roo a small pen. Hopefully this week. For now he is doing his usual thing - strolls over to our coop at 5am or so and crows, then hangs out by my girls. When I first let them out in the morning, he chases them into the bushes (with me watching carefully), but for the rest of the day he does not bother with him, just sort of hangs around keeping a vigil.
Flybybirds - He was aggressive with my smallest hen once; he chased her and pecked at her for a few seconds until she ran into the bushes. He challenged me twice, but the second time I ran back at him yelling and threw a piece of wood in his direction (not at him). He has not challenged me since! You're very right - he is most interested in what they are eating. He's learned that when I call "Here, chickie chickies!" it means treats, and he now comes running when they do! We were going to put the rooster down (our neighbors gave us their blessing, they don't care for it/him) but thanks to centrarchid's advice, we are going to give him a chance with our flock. Just need to build him a little home base first.