Rats/aggression/crowding- reference

[grieseda]

I am trying to track down a study from the 1960's where rats were given
unlimited food, and when crowding reached a certain level, extreme
asggression occurred, and the coloony eventually died out?  Or in my
senility, am I confusing research with rats with old science fiction
stories?

David Griese'
SUNY Farmingdale