First, Candy is considered an outcast given that he has simply outworn his ability to function as a worker on the farm. This is mirrored by the fact that his dog is put down for being too old. Candy can be seen in the same way which the dog is: useless and beyond help. The other ranchers' insistence that the dog needs to be put down, based upon his uselessness. Candy recognizes the fact that, one day, he will be seen as useless and discarded as well. Therefore, he is considered an outcast given his uselessness (though the men do not admit it yet--it is coming)