I think that you should "tread" carefully. (pun intended, lol)
This isn't YOUR home, this is your aunt and uncles. These are their neighbors and you are attacking their way of life and livelihood. I don't think that's terribly appropriate.
Also, I don't get where you think the use of shoeing a horse is inhumane! Horseshoes protect the horse's hooves from serious harm. Horses in captivity do not have the diet necessary to retain a hard enough hoof. This can result in serious injury to the horse. Additionally horses that are being ridden or are from working farms need that extra support as well. SO please- let them continue to protect their horses at least. If you're going to protest something, protest something that really is harmful, not helpful.
When you consider trying to "inform" someone- it's really important to ensure that you are fully informed yourself first. Otherwise you come off as looking rather silly. Then no one takes you seriously even on the issues that you may be correct about.
Another thing to consider is that people live differently. In some areas of the country, people hunt for food. They eat what they kill and use most of the animal. I find that much more respectable than the people who meander into the grocery store and toss a steak into the cart. It's MUCH more respectable than the people who go online to online hunting sites, place the cursor on top of a penned animal and click on it. That animal is subsequently killed and shipped to them. So- take into account how these people live before criticizing them and their practices. People may say the Amish over work their animals, but these people cannot survive without them and may in turn point to you driving in a car doing damage to our very environment.
Do you wear leather shoes? Do you have a Suede jacket? Do you use hair product with animal byproduct or placenta? Do you eat Jell-O or marshmallows? Do you eat Beef? Do you drive in cars? Do you use electricity? Do you use cosmetics? Are they cruelty free, not tested on animals?
This microscope can be turned on you. Why don't you start there. Ensure that YOU live animal cruelty free. Spread the word to interested parties, avoid the use of companies that are not cruelty free. BEFORE you go attacking someone else's way of life.
I think your heart is in the right place, and that's a good place to start. ;-}
I think if everyone looked to THEMSELVES to try to save the world- examining our OWN homes, vehicles, jobs, purchases, habits, needs, etc- the world would be a whole lot better off.