Toast the bread to remove the moisture, tear it into bite size pieces and set aside in a large bowl and let it cool
Shuck the oysters, separate, strain and reserve the liquor
Melt the butter, cover and saute the onion and celery on medium low heat until softened, about 15 minutes, then uncover and stir occasionally until it’s barely beginning to brown
Fold the celery and onion into the toasted bread
Whisk together the oyster liquor, chicken broth and seasonings, then drizzle and fold into the bread mixture a quarter cup at a time until it is thoroughly wetted, but not sloppy. Discard any excess broth, or add more chicken broth if not wet enough
Gently fold in the chopped oysters a few at a time and evenly distribute them throughout the mix
Spread evenly into a 9″ x 11″ baking dish
Cover with aluminum foil and bake for 30 minutes, then uncover and bake 10-15 minutes more until the top is slightly crusted