South Korean babies born on December 31 become 2-year-olds the next day.

[csziggy]

10. Wild (or feral) horses wear down their hooves more than domestic ones

They have to move constantly to find grazing and water, unlike domesticated horses, who are kept in fields of grass with few rocky areas or in stalls where their movement is restricted.

Also, wild horses self select for very hard wearing hooves, while domesticated horses are not necessarily bred for good hooves. I had one bloodline of horses with terrible hooves. Over five generations I bred that out of my herd but many breeders do not select for that and let the bad hooves be passed down.

The final thing is that wild/feral horses that get problems with their hooves simply do not survive. They cannot move around as much to graze, they can't keep up with the herd, and they become prey or simply die.