Having roosters in your flock has been mentioned periodically, but here is a more thorough look at the pros and cons of keep male birds along with your hens. There are several things to think about when keeping a rooster, so it's best to know the details before making that decision.
Needed for Fertilization
If you are not familiar with chicken biology, you need to understand that hens will lay eggs every few days of their mature lives even if they never come near a rooster. A rooster is not required in order to have eggs. What you to need a rooster for, is fertilized eggs. And you will only need fertilized eggs if you intend to have them hatch into more chicks. Fertilized eggs are also fine for eating, and you probably would never know the difference because you'll be consuming the eggs long before any embryos start to develop. Basically, having a rooster just gives you more options with your eggs.
Nothing says "rooster" more than the loud crowing first thing in the morning. Of course, in reality roosters will do their cock-a-doodle-do any time of the day and almost certainly more than just once. This kind of noise can be a problem, particularly for the backyard farmer who lives relatively close to neighbors in the city. Even if your city bylaws permit your flock, there is a good chance you can lose that right if others complain about the noise.
Though not all roosters will have the same temperament, it's a fairly accurate assumption that most are aggressive. They have a very strong instinct to protect "their" flock, and they take their job seriously. If you've raised your rooster from a chick, they are much more likely to accept you. Otherwise, a rooster can be hostile towards you and anyone else who happens into your yard (that includes people and pets).
Don't underestimate the damage that a rooster can do either. They aren't just all noise and feathers. Their beaks can deliver a sharp pinch, but the main danger is from their spurs. Roosters develop sharp bony spines on the backs of their legs, and they use them to slash at an attacker. They can do a fair bit of damage with them if given the chance. These spurs can be cauterized in chicks so that they never grow out fully but once a rooster has reached maturity, it becomes a more extensive surgery to remove them.
This is one trait that does have a good side though. A mean rooster is an excellent defense against predators, and they can stand their ground even against larger animals like dogs or foxes. And if they can't chase off an attack themselves, the commotion will almost certainly wake you up so you can help defend your flock.
So basically, you will only want a rooster if you need fertile eggs for chicks or want a protector for your flock. Of course, there is nothing wrong with keeping a rooster just because you love their bright feathers and big red combs either.
But regardless of why you decide to keep a rooster, you can only have one unless you have more than one pen and chicken coop. Roosters kept together will inevitably fight, creating stress for yourself as well as the rest of your hens.