This is the default behaviour for chickens. I can't think of any chicken like creatures that exists in the wild that resembles. The chickens I kept had plenty of room both inside and outside. Outside was a predator proof fence around a large area with different kinds of vegetation, bushes and wet and dry environments (I also had a couple of mallards). Inside they had running water, things to climb on to roost, and various boxes to lay and sleep in. Every week I cleaned their living quarters and threw down fresh bedding. They were not for food or for egg production. I ate and gave away the eggs they laid.

Edit: to keep the roosters from doing the dirty with close relatives, I swapped rooster with other people that kept poultry as a hobby

Ever heard of domestication?

PETA bad amirite?

Big logical gaps in this argument:

The op never said they were superior morally.

Even, given the above, the op deemed chickens immoral that does not make all chickens' actions immoral. Preening, roosting and eating grain are not immoral activities.

Defining only the horrible acts as horrible is a circular argument as no definition has been provided as horrible.

Other than those three, you really stuck it to the carnist, chief.