How to cook crock pot meat?

So I have a couple dozen meat to cook for a party tomorrow. I would like to start it in the mid morning and have it be ready by mid-afternoon by crock pot method. Is it better to brown the meat first in the oven for 10-20 minutes or so and drain the fat off (we used 85% burg) then plop into crock pot for 6 or so hours on low to simmer in the sauce OR should we just drop the raw meat in the sauce in the crock pot and let it cook that way? Not sure it would cook correctly the later way? Thanks ahead of time everyone.