So this scientist builds a perfect Utopia for mice. Unlimited food, water, and space. No predators. No stressors.
So what happened when life became too easy?
The mice started indiscriminately having sex with each other.
With no need to protect territory, females, or food, social bonds were broken.
Mice started turning gay.
Mother mice started abandoning and murdering their children.
Population growth stagnated.
Mice started to group up and fight with each other for no apparent reason.
All of the mice died within a few years, despite ample food and space.