The local sale barn I have worked with, Bloomington Livestock Exchange, has slaughter sales every week and feeder sales every couple weeks depending on the time of year. It is very clear where they are going depending on which sale you take them to or designate them for if they are having both sales that week. If they are at the slaughter sale they should be out of the withdrawal period.

I think having separate sales would bring higher prices since at the slaughter sale you have slaughter buyers, at the feeder sale you have buyers looking for feeders.  Probably not many feeder buyers at the slaughter sale and vice versa.

Jim