A stray thought for those pagans who feel that their religion just isn’t the same without animal sacrifice, but who don’t actually want to go out and kill a horse or something:
The whole idea behind sacrifice is that it was you willingly giving away a representation of something of great meaning and importance to you.
If a sacrificial animal came from your own stock, you had to spend the money to maintain the herd, and keep all its members safe, healthy, and well-fed. You had to buy the feed, invest in a guardian dog or two (train said guardian dog(s)), build the sheds, find the pastures, tend the wounded, treat the ill… And in exchange, these animals would feed and clothe you–either by directly providing you with meat, milk, and fibers, or giving you those things to sell so you could obtain your needed supplies. In a lot of the cultures animal sacrifice was prevalent in, people’s stock animals were their life.
Even if the sacrificial animal was one bought from a herdsman, it was still a representation of your hard work. Whatever trade you had, you had to do it well enough and long enough to have the money to purchase an animal to sacrifice. The coins you hand over to the shepherd represent your bloody knuckles and bruised knees, pricked fingertips, long days and sleepless nights.
So how does this translate to the modern age?