[xashor]

When buying Merino please inform yourself about mulesing beforehand. Those sheep got bred so they have wrinkly skin, so more surface for wool growth. They suffer and likely die when not taken care of: the wool around the buttocks get encrusted in feces and urine, and the parts get often infested. Instead of breeding further sheep that are vulnerable to this, many farmers, for example most in Australia, cut off skin, so the scarred tissue won't grow wool. Google some images and decide if you want to support such practices. If you can't live without Merino wool, check up your sources, as there are less violent methods. But in the long run it would be better if those sheep weren't further bred.

[mncharity]

Fwiw, a Patagonia shirt praised in another comment, on its page mentions "All of the virgin wool Patagonia sources is certified to the Responsible Wool Standard (RWS) from farm to fiber to help ensure protection both for the animals that supply it and the land they graze."