My guineas are also evil!!! How on earth did you get someone to be interested in them for something other than dinner?! I've come to the conclusion that I'm just not a saleswoman. My pitch is seriously lacking...or perhaps just a little too honest.
I've had my guineas since they were 5 days old. We got our chickens (hens) about a month and a half later. Everyone got along fine until about 3 weeks ago when the guineas started chasing and beating up my poor chickens on a regular basis. Two of the chickens even went to roosting a tree at night to avoid getting attacked when they tried to get in the coop at night. Once I saw it happen, the guineas got booted out of the coop and now roost happily on the coop roof. That solved the nighttime issue, but they'll still attack the hens when I let them out of the coop in the morning or if they're all in the pen together during the day. It's not like we have a small pen either, it's literally at least 10,000 square feet of fenced area around the coop. The chickens usually just leave the pen during the day. The guineas never leave on purpose, occasionally they'll have a wing flapping freak out and accidentally fly over the fence. Then they'll buckwheat and buckwheat until they figure out how to get back in. All the while sticking their heads through the fence and running as fast as their little legs and move...not getting anywhere though since their body isn't going to fit through the fence.
Yesterday I saw the whole gang of guineas (2 males 5 females) attacking, possibly attempting to molest, one of the poor chickens. I'm very tempted to offer these beastly birds to anyone who's interested in guinea for Thanksgiving dinner.