I do know that launching live animals in model rockets was banned several years before that by the NAR when several mouse launches (and bugs and turtles, lizards, goldfish or anything else anybody could fit in a payload section) made the news and drew sharp protests from the ASPCA (and occasionally some legal hassles) if things went wrong and the mouse ended up dead.
I believe G. Harry Stine said in several editions of the HBOMR that unless you were a highly trained forensic veterinary specialist with access to massively expensive facilities and equipment, there was nothing you could learn from launching a mouse or any other animal, other than just whether you killed it or not.
In fact I am pretty sure the long-time model rocketry practice of egglofting was in fact devised in the early 1960s to create a way for average rocketeers to challenge themselves by launching a payload (i.e. the egg) roughly the size and fragility of a mouse and recovering it without serious damage -- without putting the lives of any living animals at risk.