Yup yup!

At the moment we don't know what is going to happen, so future decades will show what will come =)

Also, in my experience the same happens with domestic herd animals, too. Pack too many cows in a too small area, and they start hurting each other. Generally speaking horses are peaceful creatures and seek to stay away from fights - they find their comfort in the proximity of the herd. But enclose too many horses in too small an area, and soon they start to develop aggressive behavior.

I think that the amount of physical space is one element in it, but there is more variables, too. Each animal (humans included) have some basic needs, which they need to satisfy - and failing that, they develop ill behavior. Personal space is one of those needs, and maybe we could name things like dignity, self-esteem, enough of meaningful physical exercise, a healthy amount of challenges, and enough time and space for rest, play and creativity. And, especially for herd animals; meaningful interactions with the other herd members. Things like that =)

There are studies of domestic horse feeding - and those studies show that domestic horses who are constantly overfed have more health issues and behavioral problems. But horses who sometimes have to seek for their food are healthier and happier.