We have several options here in Va. Our county has just formed an assoc to try to promote "lots" of cattle. Trying to somewhat model it after the Botetourt County cattle assoc. They have basic protocols, that all follow, certain vaccinations etc. Thing is, they market a couple of times a year and will take any size if they "grade" , as far as type and such. They have developed several outlets for the cattle so might have 10 of the 450 wts, 20 - 500 wts, 7 - 650 wts., 25 - 8wts. . This allows farmers calving different times or having bulls in all the time so they have a half dozen calves of different sizes, a chance for those calves to match other farmers calves. Have to be weaned 30 or 45 days minimum, Have to be steers no bulls, I think they are marketing some heifers.... but if you have 3 of 4 wts, and 4 of 5 wts., and they all meet the guidelines, they all will get co-mingled in with thei sized calves, and go into a "load". Also have the one stockyard that does graded sales once a month. The calves have to have certain type (no dairy, no "eared cattle") must be at least 400 lbs., and they are all co-mingled. It really helps us with "colored " cattle that would get "killed" at the regular sale where they can only see "black". They prefer them weaned but I am not sure it is required there.
If anyone is interested, they could get in contact with the extension service in Botetourt County, Va.... Or even call the stockyard in Hollins Va. They allow this group to use the stockyard for weighing and such. The Rockbridge Co Cattleman's assoc is the one just starting up.... you can get info from John Benner with the Augusta Co., Extension service.
Might help you get something to use as a model to get one going in your own area. And I think that if a farmer were in the general area, either might take outside cattle if they met the protocols. You would have to join the assoc....
There are some yards that do "graded sales" and those cattle do get co-mingled into uniform sizes....The commission is a little higher because they actually have a state grader there to determine if the cattle make the "grade", but around here it helps with the smokey and red calves.