Random animation starts for duplicate animals

It looks great to have a swarm of animals rather than isolated individuals but it looks very strange to have then swimming in synch with each other, or all of the cats washing exactly the same. I don’t know if it is possible to start the animations randomly at say 0, ¼, ½, and ¾ of their play loop through? Otherwise might it be possible to set a start time in their loop manually in a way that is saved?