Here at the couple of local sales, your cattle are sorted off the truck into any "uniform" groups of your own... then weighed and then they run them into pens. We get a printed sheet right out of the scale house....number of head in the group, back tag numbers or marks, pen they are put into....... used to be hand written tickets before they added the electronics in the scale house. There is no shrink added to the cattle. At some of the sales they will have a grader come in and they will group similar calves from different consigners into a "graded pen" so that the buyers can just buy bigger groups. It USUALLY is beneficial to the guy who has one or two of 4 wts, and 3 of 5 wts etc... if they are nice calves. But for the most part, if the seller has singles or 5 of something, they are just your own animals. The sorters will put similar ones together of your own and pen them that way.
We took in 20+ head and had 4 singles, several were paired together, also had 2 groups of 3 each. Heifers are sold separate from steers, and bulls separate. Our closest yard changed hands after 50 years or so and we are not thrilled with the new owners or the situation. It is becoming more of a "clearing house" for the new owners to have "sales receipts" for cattle they ship out, and getting to be more of a "good ole boy" thing. Fewer and fewer cattle come through this yard than used to. There are a couple of other stockyards that are another 30 + miles from this one, so twice as far away from us.... but we have sold at one a few times and are seriously thinking about going back there more. I just am not happy with things here at this one and have voiced my opinion to my son here the last couple of times. We are by no means a "big" place but ship 100+ head a year so not exactly a backyard hobby farm either. In this area most herds average less than 50 brood cows.... lots of 20 and 30 cow farms. Sometimes we will run 50 through at a clip, but often it is a load of about 20 as we buy and sell a few along too.