Pictures of the goats in question will probably allow us to determine breed/cross.
What are you going to use your goats for? Meat? Milk? Because honestly, you could pay a little for a couple good specimens that would eat down a pasture just as well as a cheap/free animal that you don't know the heritage to, isn't registered, has poor conformation, or brings diseases to your property. With better stock you will get better results and it will be easier to sell higher priced kids on a yearly basis.
Goats are often fed free choice hay. Alfalfa is best with pregnant and lactating dairy goats. Grass hay is fine for meat or non lactating does. (I raise mini meat goats and have a few dairy goats. They all get free choice hay, but late pregnancy/lactating does of both types get grain with alfalfa pellets in it)
As for grain, you DO NOT NEED TO FEED ANY GRAIN unless the does are in the last few weeks of pregnancy or being milked. Other extra grain will only fatten your does and they are a lot worse off to heavy.
Also, if there are any buck kids they will NEED to be fixed before they hit 10 weeks of age or be separate from the does, as they can and will impregnate their way too young sisters or rebreed the other does in the herd much too soon. (Intact male goats are called BUCKS, not billies, as adult females are called DOES, not nannies... Young males are bucklings and young does are doelings... Fixed males of any age are called Wethers) Wethers are pretty much only good for cart/pack, pets, or meat.
As for shots, they need a CD/T booster once per year, within a month of kidding out every year to allow carryover to the kids. If your area is selenium defecient, they should get a BoSe shot within a month of kidding, and the kids should recieve them at birth and yearly after that.
As for the fencing, you should be fine. Most goats stay just fine in a pasture. However, don't allow them any means of learning to escape, because after they know they can escape nothing will hold them in. Make sure the fencing is safe, and if your does are horned that they cannot become stuck in the fence. In fact, if they are horned, give serious consideration to passing them up, or keeping them only temporarily... Just long enough to breed them to a desireable buck, kid them out (and disbud those kids) then sell the origional does.
My biggest advice is to learn about goat diseases. I am currently eliminating CAE out of my herd. It sucks, and I must say I"m surprised at the general ignorance that many people have with diseases. I find it despicable, as do many who care about the future of goats and are working hard to better their reputation.
Check out these websites:
My website :
www.freewebs.com/capriceacres/ (feel free to email with questions if you'd like)
Fiasco farm :
www.fiascofarm.com (an AMAZING goat site. I don't agree with all of the things they do, but a lot is quite good info)
And of course, stick around this site. It has been very helpful in the last 2 or near 3 years I've been online.
Get a few good goat books and read up. Most stuff you'll have to learn as you go.
good luck, and we want pictures!!