I disagree about cats. I do not mind having a couple of spayed/neutered barn cats, but letting them breed and kill things is bad. If we allowed native species to thrive, they would eat the mice. Where I live, I have seen gray foxes, red foxes, white weasels, and other animals. They can all eat mice. Cats were brought over here in the 1600s. Before that, were we overrun with mice? NO. Actually we have more mice now, since Norway rats were brought over here on Columbus's ships.
I have not been able to read any of Joel Salatin's books yet. Any recommendations? I have seen pictures of his farm, though, and I love the pastured rabbits! Bunnies should be on grass (if possible)!
Actually, even before the English breeds, the first chickens came from China.
And I don't have chickens, just ducks and geese at the moment (and guinea pigs and cats and mealworms).
I think farm animals are different than invasive species, because, farm animals just stay on a farm. They don't go out and kill wild animals for food (or eat all of those animals' food).
I'm not saying non-native species should die out EVERYWHERE. I just think they should be kept where they belong. I'm not saying we kill sparrows to PUNISH them. No. We should just kill them because it's better for the rest of the birds. Think of it like this- let's say, you have a big flock of chickens. One day you bring in a new chicken, but you realize it has mites. Do you put it with your other birds? No. That would be cruel to the others. Instead you treat the new bird, and if that doesn't work, you would have to cull it. It's not because you hate the new bird- you're just doing what you have to do.
Actually, I only learned about the food chain and natural/invasive species for about quarter of a year in sixth grade. And I was taught by the woman whose grandfather killed the last native wolf in CT (she bragged about this, like it was a good thing!) So, if you want to learn about this stuff, you have to experience it... sadly.