Agree with Cathy. I usually put the meat, whole, in a roasting pan on a rack...
...with a little water in the pan. Then I seal with foil and set the oven on 275 to 300 degrees and leave it, undisturbed, for about 5 hours to 8 hours. I start checking for desired tenderness at around 5 hours, but usually leave it longer, closer to 8 hours.
Then I up the oven temp to around 400 and brown the outside (foil off, obviously).
Works for me.
Michael