Pros of keeping a Rooster`
Rooster is a guard.
Typically he will herd the hens to the safety of the hen house if he thinks there is a sign of danger. He will also try to fight off an intruder. Roosters have spurs on their legs which they use for fighting and protection. A rooster will try to protect his harem.
A rooster, as mentioned above, is important for reproduction. A good rooster can service 20 hens or so, although often they are kept with only half that many to ensure high fertilization.
Roosters have been said to offer control over pecking in hens. Hens in some situations will peck to death one that is weak. Some keepers report that having a rooster reduces this problem, although it can also be reduced by keeping the hens in smaller numbers and giving them plenty of exersise.
Some breeds of chickens have very attractive roosters, for a person looking to add a splash of color, a living decoration, on their farm, having a big, fancy, rooster will certainly fill this role, and they are not as much work as peacocks.
Roosters are charming as they crow to welcome in a new day.
Cons of Keeping a Rooster`
Some roosters become aggressive to their keeper. They will even chase people away from the hens. This is certainly more common in some breeds of chickens than in others.
Not everyone enjoys the sound of a rooster crowing first thing in the morning.
Roosters will fight each other if too many are kept in relationship to the number of hens.
If chicks are not wanted, the rooster serves no purpose, but he is another mouth to feed.
Roosters are larger than hens, and therefore are usually more work to handle.
Roosters are not as easy to sell as hens, a good laying hen will generally sell for more than a rooster of the same age.
If a person is going to eat some of their birds, it should be noted that roosters are not as good tasting.
(all info from Brenda Nelson Hilium blog)