I don't think animals were hurt in Texas Chainsaw Massacre, I've never heard of it at least. There are few animals in it, maybe some chickens I think.The shoot was hard on the actors though.Yes, I love method acting and realistic effects in filmmaking as much as the next person, but I can’t stand the idea of film makers actually hurting animals in order for their horror films to be more realistic, this is why I’ve never watched the Texas Chainsaw Massacre.
Cannibal Holocaust is infamous for its killing of animals, but I do believe the indiginous people that appear in the film (as the cannibals of the title) ate some of the animals afterwards (monkeybrains seem to be especially delicious). Actually I watched the film and while it's no fun to see animals killed, it's not really different from watching a nature documentary where animals kill other animals. The worst bit is where a turtle is very slowly and apparently painfully killed.
I'm surprised the film is still available, as the killing was done illegally and the filmmakers went to court over it. You'd expect a film like that would get banned altogether. Still it has its fans, among them Eli Roth, who did his own cannibal movie which was much tamer (and in which no animals were killed obviously).
As much as I love Italian Gothic horror and giallo (Italian thrillers) from the fifties, sixties and seventies, I never cared much for all the zombie and cannibal films from the seventies and eighties; they're just too stupid and often disgusting.
Still animals were killed (and treated badly) in more mainstream films too, like Apocalypse Now for example. And many westerns were known for treating horses badly. I think nowadays there's far stricter control for that, although even in a film like Pet Sematary, though it's done by professional trainers, they still rile up cats to become as angry as you see them in the film, so it's a thin line between 'training' and abuse.