And aren't we glad we didn't fall victim to "natuerliche Auslese" (natural selection) or--worse--selective breeding (as favored by Hitler)!
Seriously, natural selection has ensured the survival of the physically strongest for millennia, but I think there are also other qualities in humans (and animals) than being physically strong. Mind you, this is a subject philosophers and wannabe philosophers have written many books about.
I personally would never discard a runt-of-the-litter animal, but I would not necessarily want to breed it. With humans, this issue is a bit more complicated. Yet renouncing hygiene is certainly not the answer.
So, let's cuddle our beloved chickens, cats, and dogs, and then, by all means, wash our hands before we touch our faces or handle food.
Btw, we have included in our Last Will that all our animals (27 cats, 2 dogs, and 8 chickens) are to be cared for as they are cared for now and that the chickens shall never be slaughtered. (We also no longer eat chicken and pork and only eat beef [with occasional exceptions in restaurants] of free-range cows, who, at least, had a happy, if short, life.)