They go into a sturdy round pen within another small pen. All the horses can see each other and communicate but no interaction between them. If they're rideable they may be ridden that same day or the next. Depends on how early or late in the day they arrive and what the weather is like. Once quarantine is over then the others are allowed in the small pen one or two at a time to meet through the fence. Whichever ones they will be out with will stay for a day or two then they'll be put in their designated pasture together.