My father has used horses to pack out some elk during archery season. I'm not sure where he sources them, but usually goes to the local town and someone knows someone.
I don't believe it's unreasonable, and they will deliver and help or sometimes I think they have left the horse for a day or two with some food.
Only rented when there was an animal down in a less than desirable location and difficult to pack out. Worth the $'s usually.
Sometimes people trip and fall down stairs.
Sometimes assholes push people down stairs.
That doesn't mean "stairs are bad" nor does it make someone who pushes someone down the stairs any less of an asshole.
I believe our party pays about $450 a week per horse. My actual experience is limited to riding on a circle track as a kid. However I have been hunting with this group for 10 years and they pack, first 1 horse, then 2, and now 3. We hunt an area about a 1-1.5 hour hike up. The horses are used strictly for packing and not ridden to hunt.
The big advantage is packing gear up: tents, stove, food and most importantly your elk out. They carry more stuff up then I see people use car camping. Since we are close we have put a whole elk on 1 horse, 4 quarters. One load will be tack and food to care for horses. We buy hay and pellets at Murdochs or a local feed store. If you are much farther up, say 2-4 hours then you will have to lighten your loads and also can 't make as many trips in a day, we can make 3-4.
Panniers make it easy to pack, just keep everything balanced and low. I have learned a lot watching and assisting but still a novice. There are some websites, books and social media pages for packing.
From what I have heard too, I think using the horses to pack not ride is a good idea. You can still get hurt but much less likely then if riding the horse around. Plus what to do with the horse when you want to hunt, you tie it up starts pawing, whinning etc.
Good Luck.