Although many chicken owners shy away from keeping a rooster or simply aren’t allowed, there are numerous reasons to keep a rooster with your flock. The number one reason is protection. A rooster will protect his hens from predators if at all possible. If anything, his defense will buy them time to get further away. A good roo will also make sure that his girls have good things to eat: If he finds a bug or good treat, he will call his girls over and give it to them. His instinct tells him that healthy mates are most likely to produce healthy offspring. Clearly, another reason to keep a rooster is fertilization. With a ratio of about 1 roo to 8-10 large fowl hens, eggs laid will be fertilized. This does not mean they contain an embryo; it simply means that a blastodisc of multiplied cells is present in case conditions for growth are present, and your fridge does not present the conditions for growth. Collect eggs daily, and fertilized eggs are nutritionally indistinguishable from nonfertilized eggs. However, you can increase your flock by setting fertilized eggs with a broody hen or incubator if desired.
There is a great article by Harvey Ussery on his website themodernhomestead.us entitled “Working With the Cock(s) in the Flock” which explains what a good roo should do, inter-roo dynamics, and how to deal with aggression. Here is an article about “Dealing With Rooster Spurs,” and here is excellent advice for keeping your rooster sane and in his place from “The Easy Chicken: For Beginners.”