While it is possible to cook thin cuts of raw meat in a slow cooker, you should avoid cooking large, raw slabs in one. As you probably know, raw meat can be dangerous to eat, especially if left at lukewarm temperatures for long periods. When slow cooking with raw meat, you need to make sure your device reaches at least 140 degrees Fahrenheit in under two hours. Otherwise, you risk food poisoning. Because of how they are designed, slow cookers aren’t great at retaining heat and often take several hours to reach a safe cooking temperature.
You might want to consider investing in a meat thermometer to make sure the meats you cook reach safe temperatures. To be safe, brown meat a little before placing it in the pot. If it’s a thick, hearty meat, it’s better to use a pressure cooker, oven or other cooking method, since it will cook the meat faster and more thoroughly.