It seems strange to point out how well you are treating an animal when you are slaughtering it for consumption in the end. In fact that is the animal's only purpose of existence.
From an evolutionary point of view you could say that cows, chickens, pigs (and cats, dogs, horses) are one of the most successful animals, exactly because we eat (or pet) them.
I mean yes, in the grand scheme of things, treating animals well before slaughtering them is better than treating them poorly, but it misses the forest for the trees.
It's only a matter of time until lab-grown meat is as good and cheap as the original, and then society will turn. Eating real animals will be something like hunting is now, a tiny thing and with huge image costs.
As anecdata, consider the outlawing of fox hunting in UK, declining hunting love in France[0], and a similar decline in the US[1].
The more hunting becomes unusual, the higher the number of people who will consider it in negative light compared to those who view it favourably.
[0] http://www.bbc.com/news/magazine-37865215 [1] http://deerfarmer.com/wiki/hunting-decline
Furthermore, whilst it may not be obvious in activist circles, seeing the topic was about eating animal produce, the obvious counterpart in hunting would be game animals, and not a sport (which fox hunting is, more or less). My (unsourced) guess would be that most non-vegetarians do not condemn hunting, and it would also be a somewhat hypocritical stance. Furthermore, meat consumption isn't exactly on declining in the world, but you can make your own conclusions about that.
(I'm a city dweller, and haven't hunted anything in my life. I'm not saying that to validate my opinion, but regardless I know quite a bit about the realities of hunting that probably apply to most places, and the reason it is in decline may well not be because of a shift in the moral landscape. It is a consuming hobby, but that doesn't in itself imply that all non-hunters would automatically start to disapprove it more and more.)
It is obviously an opinion not a fact, but as an example, you can consider the attitude of people to eating animals that they ate in the past and not now (porcupine, turtle, cat, dog).
Not only it's considered disgusting, but it's often considered worse than eating other animals.
Perhaps that will convince me to stop eating meat. Meanwhile I have bigger worries.
I can dig the exact page from On Food and Cooking for reference if needed.
Stress should be avoided, don't get me wrong, but I don't think our tastebuds are this advanced.
From the farmers point of view.