By not fixing the cats…

Unneutered males fighting will cause abscesses. If the abscesses are left untreated, they will get infected and are horribly painful for the cats.
Instead of a warm bed, these cats have rocks to sleep on
Unfortunately, this is a normal site with feral cats living at auto centers
This is a typical feed site - food strewn everywhere and none of the cats fixed
Two unspayed females and their babies
This little guy can be snatched by an owl, hawk or coyote