Guineas do not understand "behave".
They understand "do your own thing" or "go your own way".
Yes, they can be housed with chickens. Actually our guinea hens lay their eggs in the barn and both hens and cocks are out forage for the entire day, rain or shine. They have a different area of the barn with high roosts, but like to freak out the chickens by taking one of their roosting spots every once and a while.
They forage all day, come in for scratch treat, but don't like to come in early - they want every bit of daylight outside. Scratch time is another time that they mess with the chickens. But the chickens and a couple of our roosters give it right back - no blood shed.
Be prepared for the noise. They can be loud, anytime, all the time, for any reason.