Rhino horn for example regrows at about 9cm per year, which is worth very roughly $2000-$15000 (I'm unsure about recent prices). So they can be farmed and have

Rhino horn for example regrows at about 9cm per year, which is worth very roughly $2000-$15000 (I'm unsure about recent prices). So they can be farmed and have decent lives. The trick is that if the price is high they're still going to get poached. If the price is low then it'll be too costly to feed them and it won't be worth it in the first place.