Remove chicken from package and be sure to remove goods from the cavity if there are any. Pat the chicken dry and slather with butter. Generously season the whole chicken, inside and out, with the lemon pepper seasoning. This next step is optional: create 3 tin foil balls about the size of lemons and place them in the bottom of the crockpot. This will create a platform to keep the chicken from sitting in its juices. Place the chicken, breast side up, in the crockpot. Cook on LOW for 7-8 hours.
Sauce/gravy: once you have removed the chicken from the crockpot, crank it up to HIGH, add the half pack if chicken gravy, and the juice from half of the lemon. Let it simmer in the crockpot for a few mins. You can also do this in a pan.