You can OP. I find thighs work better than breast in a slow cooker though.
My fav recipe for putting it in raw is:
Chopped onions,
Chicken thighs,
Button mushrooms,
Red peppers,
Sweetcorn,
Red pesto,
When you are ready to serve stir in some cream or crème fraiche.
You can do a nice slow cooker lamb:
Put in a raw leg of lamb, spike some holes/cuts in it with a knife, stick little bits of rosemary and peeled cloves of garlic in the holes, bung a good glug of red wine over the lamb and cook. You can add the juices to some gravy granules (make up the rest of the liquid with boiling water).
Also you can make a nice veggie bolognaise.
Chuck in some onions, chickpeas, red peppers, beans, sweetcorn, lentils, carrots (really any veg you like), passata, yeast extract (branded marmite is a waste of money!), herbs eg oregano/mixed herbs, a mug of stock or a glug of red wine.
Most other slow cooker recipes I will quickly fry the ingredients first then put in the slow cooker to thicken up/soften/improve over the day and so it’s ready to serve when I come home.