When cooking meat in the slow cooker you don't have to submerge the meat in the slow cooker but you should put some water or broth at least halfway to cover part of the meat to be cooked.
You can basically simmer the meat in the slow cooker but make sure the slow cooker doesn't evaporate all the water and have no water or broth in it.
Otherwise the slow cooker cook burn the meat and crack the cooking pan part of the slow cooker.
So make sure you have some water in the slow cooker but the meat cooks much better when fully submerged in the water in the slow cooker.
The meat such as chicken and pork will become softer as it's cooked submerged making it easier to chew and digest as well.