for me, to kill and eat an animal that you have love and affection for would be like cannibalism.
Somehow not having the love and affection connection/bond with a pre cooked chicken purchased from Tesco, means that I can eat the chicken and be fine about that (detachment) . We had a pet duck when I was growing up. I could not have eaten him ... or our rabbits, but now I can and do eat duck (occasionally).