Unless we are going to the vet for a specific problem on one particular cat, we take all 6 cats in at once. We have 3 dog carriers that can hold 2 fat cats each. There is NO way we'd get away with taking only one or two at a time. They would get the hint that something was up and would all run and hide, never to be found until it was feeding time. It works best that I grab 2 of them at once and shove them in carriers. Seems cruel, but it's the only way it would work. Jake is way too smart and knows when he's trying to be caught, and Callie runs if she doesn't want to be bothered (most of the time, unless she's on the bed). Once those two are caught, the rest are easy. Plus, we get a discount with 6 cats in at once.