I suppose most of you have attended a church service and then gone to a community barbeque. Keep that in mind as you read this.
The Greeks, and virtually all the ancient peoples, had a few habits with a high yuck factor for moderns. One of the more yucky bits was sacrificing animals in religious rites, which they did frequently.
I suspect some people have an image of a crazed Greek plunging his knife into a squealing, struggling animal as the blood spurts everywhere and the crowd chants chthonic prayers.
Nothing could be further from the truth. The whole thing was very orderly.
In the Greek mind, it was important the animal "agree" to be a sacrifice. An unwilling sacrifice, one which struggled, was considered an ill omen. If any Greek priest had conducted a sacrifice like I just described, it would have been like the vicar turning up drunk for the sermon.
For days before, the selected sacrifice was treated kindly. It was given good food and made as comfortable as possible. Most sacrifices were sheep and pigs. Goats were a common standby. Oxen were luxury items for big events.
The sacrifice would be led from its farm to the temple. The sacrificial altar was put outside for obvious reasons, probably by the front steps. During whatever was the ritual for the particular God or Goddess, there came a point where the priest would take out a knife and quickly slit the animal's throat. This is a perfectly standard way to kill any farm animal for butchering, and in an agrarian society, virtually everyone would have the skill.
The blood was caught in a bowl and I presume was given to the God or Goddess.
A priest would then open the body and check the liver and entrails to see if the God or Goddess was pleased with the sacrifice. I expect the answer was always yes, unless there was something pathologically wrong.
If a Classical Greek saw one of our modern abattoirs, he would be shocked at the impiety and disgusted at the process. Not because of how many animals are killed there, but for the lack of respect shown the animals. The average animal sacrificed in ancient Greece probably died happier and in greater comfort than the steak you eat tonight.
Speaking of steak...
After the sacrifice the victim was butchered by someone who knew what he was doing. The long bones and probably some offal were burned in a brazier for the God or Goddess to consume. The rest of the meat was barbequed on the spot and everyone stayed for a community picnic!
If you were the child of a poor laborer, quite possibly the only meat you would see in your life was that given to you at the public sacrifices. The sacrifices were donated by rich men, and therefore were a roundabout way of donating quality meals to poor families. Animal sacrifice at the temples was, weird as it may sound, a community service.
This might seem a roundabout way of delivering the picnic food, but ancient Greece had a distinct lack of refrigerators. Without them, meat could not keep for long, even if it was preserved in sea salt. The only way to ensure the meat at a BBQ was fresh and healthy to eat was for it to arrive still breathing.
So the whole thing was nowhere near as yucky as you might think. Something to ponder the next time you go to church and then a barbeque.