The poem in the other thread that Q linked to above—although it is called there BUNKHOUSE CHRISTMAS and attributed to S. Omar Barker—is not the same poem that is quoted by montanahorseshoer above.

The CowboyPoetry.com says the title is EMPTY SADDLES AT CHRISTMAS, and it is indeed by S. Omar Barker, and it was originally published in "Western Horseman" in 1966. Furthermore, it won a Spur Award from the Western Writers of America in 1967. So its origin is fairly well documented.

The entire text is given there, and it is somewhat different from montanahorseshoer's, but since they have gone to such pains as to obtain official permission from the estate of the writer, and have posted the customary warnings about unauthorized copying, I'd rather not copy it here.