I recommend getting the barn cats neutered/spayed to prevent further breeding and leaving them where they are. Take the adults in who need medical attention. Then take the kittens in because kittens get placed faster. Sadly, no one seems to want adult cats during kitten season. They will sit inside an already cramped small building with other cats that they probably won't get along with for a very long time. Basically, you won't be doing them any favors.
Call first
If you do bring them in I suggest bringing them in a crate. They won't take them otherwise! But I do agree with Jamie!
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