these are our prey, I'm not sure it's part of the natural world to care too much about the comfort of one's food source.
Furthermore, many within a species are not at all "humane" to each other, have you ever seen how a rooster treats his hens or hens treat each other? Mine were well fed, free range in a fenced 1/2 agree of grasses and more feed stuff, and yet the 5-15 hens and one rooster (who had to go after he had pecked to hens nearly to death having plucked all their feathers trying to catch and mount them) I had over the years could be ruthless to each other if the mood suited them. I've seen similar in other farm species where certain alphas have to be kept separate due to the likelihood of them hurting the youngsters or mothers, etc. So the idea that because they are potentially conscious, doesn't guarantee in any other real world they might exist, anything akin to humane treatment.
All that said, we are humans and should be able to rise above the apparently natural disposition of not caring about our food sources or worse causing them unnecessary discomfort.