Chickens don't really attract rats, the food you feed them that does. So don't feed them more than they'll eat in a few hours and let them out to scratch in your yard.
I've seen chickens chase mice and swallow them whole. And they'd do the same with a small rat. And I mean the whole flock chasing them until it's caught and consumed.
Roosters can be an issue when you have neighbors close by. They'll crow all day and even in the middle of the night, and always at the crack of dawn. And they get "cocky". They grow spurs in a few years and they will use them on you, and your kids.
My advice is you buy a few hens, year olds are a good start. If you buy chicks make sure they're sexed and know you might still get a rooster.
And, yeah, the eggs are better than store bought, and often a lot better.