I can't recommend you get chickens to control fleas and ants. Chickens aren't going to search out those pests so you should look into non-toxic alternatives. Plus, in the long run, the alternatives will be a lot cheaper!

Roosters aren't needed in order for hens to lay but you first need to see if you can legally keep chickens in your area. Then you have to provide them protection from predators and housing so they can safely roost, lay eggs and have warmth in the winter.
They also need a nutritious diet so buying feed for them is an ongoing expense.

We raised chickens for years. Yes, hens will lay eggs but they are infertile. You will need a rooster to get eggs that will hatch and become chickens. There is lots of info on the internet regarding free-range chickens and no, you don't ever clip their wings. Free range chickens must be able to fly to protect themselves from predators. We would still be raising them if the winter wasn't such a problem and if we could sell the eggs to offset the cost of feed. You do need to give free-range chickens grain mainly in the winter when there is little to forage but also to supplement their diets in the spring/summer/fall.

Go to the Farm Forum on this site for lots of info about chickens.

One other comment. Yes, chickens get rid of all sorts of garden problems and even help you weed in the early spring! But, you definitely need a rooster if you are going to free-range. Your rooster is the 'bodyguard' and will protect them from danger from above (owls, hawks, etc.). It is an amazing experience!

Patty,
If you want chickens, by all means get a small flock of hens. I can't recommend getting a rooster for a beginning "mother hen" because they can be aggressive. Get chicks, handle them often, get them used to you, and they will follow you around the yard. They are great for catching grasshoppers and Japanese beetles, but fleas and ants, no. Don't clip their wings--they need to fly to get out of danger.
Before you get hens, get a good book that covers selecting breeds, and raising, caring for, feeding and housing chickens. I recommend Chickens in your Backyard by Rick and Gail Luttmann from Rodale Press. It's straightforward, easy to understand, and doesn't make rocket science out of having a bunch of cluckers wandering about.

Thanks guys. Yes I am zoned, the lady two yards over from me has them and is loving it. I am thinking 3 or 4 and know a coop of some sort is necessary. Just wondering from you folks who have had them or have them, how rewarding and fun it is to love and care for hens. I will look for that book and have read some on web.

I have kept a flock for years. I used to raise them to sell eggs and breed my own. I stopped selling eggs last year, but still keep two dozen hens and a couple roos.

I love having my flock, and it's a part of my life, but be forwarned, just like any other livestock, there is a lot more care to keeping a good, healthy flock than you think. Just like with goats or horses. If you want them because you want chickens.........then be prepared and go for it. If you want them for flea control, you will find just buying front line is cheaper and easier in the end. LOL.

More than anything, they need protected, and if you are talking 'yards' and zoned, instead of acreage I doubt if you will have living chickens very long if you try to free range them. They do cross roads (why does the chicken cross the road is one of the oldest jokes on earth) and they do fall prey to dogs, racoons, weasels, fox and ornery kids.

The farm forum is a great place to get an earful on chicken husbandry.