The yard and the commission company work on a set per head fee. You also pay insurance, beef check off, yardage and a sales staff fee. The commission company charges for feed determined on how long they are there. It sounds like a lot but usually runs around $32 per head for mine being fed two days with the day of the sale being one. Its real feed, not hay. Quite a bit cheaper than the barns in this area that sale on a percentage especially with cattle as high as they are now. Commission savings is one reason I can afford to ship them as far as I do. Shrink savings and a better than local price is the others. I can't get paid locally for selling vaccinated and long weaned calves.
You technically unload your own animals into one of their pens where the yard workers get a count of you animals then move them to a set of pens in the commission companies part of the yard. Its a very big place.
From there the commission company man determines how to sort them, feeds them, and gets them moved to the sales ring on Monday. He is in the sales ring with them and setts the opening price. If he does his job, he lets the auctioneer know of their vac history as well as days weaned and anything else that might help them sale better. He can also pull one out if it got hurt shipping, is sick or just doesn't match the others. Those will sale the next day.
He pays you as well as your freight company if you hired someone to bring them in. He also handles the problems like if you have a insurance claim or if a heifer proves out pregnant after you guaranteed them open.
The yard workers handle them after selling, and through the load out process.
It works very efficiently and why they can move 15,000 head in a day if need be. This is at the Stockyards. OKC West works the same way except the commission company work is done in house.
Picking a commission company is not real critical as they all work pretty much the same way. Some sort a little different than others. Its a matter of trust and service and as shown from my problem above and can help build a reputation. I picked one of the smaller companies hoping I would get better service for my small groups. Western is by far the biggest and did mine for years but I felt my calves kind of fell through the cracks as I am such a small producer so I switched. The man I use knows my calves won't be the best but they have had their shots, are weaned what I say they, are and are healthy. His order buying company will buy a lot of them.
Commission company's used to work all the big yards. My dad was one at the Ft. Worth yard back in the 50's. Back then they sold directly from the pens. The buyers and the auctioneer all walked through the yard.