Animal welfare efforts don't interact with, and in fact are contradictory to, the vegan position: vegans don't try to make farms and slaughterhouses more humane, we try to abolish the exploitation and slaughter of sentient animals entirely. If animals deserve to be treated well, surely they also deserve to not be exploited and slaughtered (those are the traits of sentience: the ability to feel pain, a deep desire to live and to have bodily autonomy. Therefore if some traits of sentience are important, why not other traits?)
But even if welfare was worth pursuing in the exploitation and slaughter systems - us as consumers don't have access to high welfare animal products: the welfare labels fail to uphold the little welfare they claim to uphold, horrific practices are considered high welfare (eg. gas chambers and male chick macerators), and small farms don't have higher welfare than big factory farms.