If you live in north america housecats belong indoors,

I would have mama cat spayed and recovered from surgery before letting her out. Otherwise their will just be more kittens. We had a family of feral cats that lived under a shed where we used to live. The kittens hung around mama cat for a long time. One of the grown older kittens had her own litter. They were so wild we couldn't catch them. We finally got a trap and had them all spayed and neutered and three of them live with us in our new house. Mama got killed by a car.

Check with your local humane society--they often sponsor free/low cost spaying and neutering clinics. As caavonldy said, get ALL the cats spayed or neutered, and continue with their shots. Let the kittens outdoors with their mother when they are about 8 weeks old. Bring them in at night or when their mother comes in. As they get older, you can let them stay in a secure spot (perhaps in the barn) overnight. You will probably lose a cat or two.
The kittens will be intimidated by most full-grown chickens. However, I would not trust a grown cat around chickens. Barn cats are wonderful for keeping down rodents and scaring away small predators (possums, etc.).
Some cats hunt, some don't, but their presence in a barn or outbuilding will deter some rodents/predators.

Thank you!
Yes will keep up on the shots, etc. The mom will be spayed as will any kittens we do not place.
Today they are in an outdoor pen.
The mom has been very good with the chickens and having the kittens outdoors in the pen with chickens about should get them used to poultry. These are very tame cats--I would have them in the house except that I'm allerrgic.