I have the view that anything that screams in pain when being dismembered alive, because the throat slitter missed (this is how chickens are killed - hung upside down by their feet, and then pass along a line where hopefully a throat slitting machine cuts their throats for them but if it misses, the chicken is just ripped apart alive) is something I couldn't eat. And yes, I have seen it.
Neither could I eat an animal that has experienced terror and pain as it is goes through the passageway of the slaughterhouse to be killed (whether "humanely" or not). And slaughtermen are somewhat deadened to the suffering of the animals and it's the last of their considerations.
Any being that fights for its life, feels pain and terror, raises its young and would defend them if it only could, seems to me to be very different to a plant which is non-sentient, feels no terror, experiences no physical agony.
However, I know I seem to be in a tiny minority on this board.