Back when I first started using a "Crock-Pot" (back in the 70's when I was going to UT) - boneless and/or skinless chicken was not a "thing" like it is these days. We just used a whole chicken, cut it up, and used it with bones and skin.
There is no reason not to use the skin-on/bone-in chicken pieces. No, the skin will not be crispy like when cooked in a dry enviroment (roasting) ... a slow-cooker/Crock-Pot is a moist cooking method - so even if you brown and crisp the skin first it will get "soggy" during cooking. Browning first will add flavor from the browning - but it's not going to be crisp after cooking.
But, as Paul Harvey used to say, "Now, for the rest of the story."
Removing the skin will remove some fat and calories. However, the skin, and bones, also contain collagen - they are natural thickeners (gelatin) and add flavor enhancement and mouth-feel (unctuousness).
It's really a matter of choice. Do it which ever way you want.
Personally - I have never had a problem with leaving the skin on.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain