In a large skillet, cook sausage, onions, and celery, breaking apart the sausage as it browns. Once the sausage is fully cooked and veggies are tender, remove from heat.
In a large bowl, add bread cubes. Pour over chicken broth and eggs and toss to coat well. If the bread is soaking up the chicken broth quickly and seems dry, add in some extra broth.
Stir bread cubes with cooked sausage, veggies, salt, pepper, and poultry seasoning. Pour into well-buttered casserole dish. Dot the top with butter and bake at 350 degrees for 45 minutes to 1 hour. If you don't want the edges or the top to get crispy, cover with foil while baking. Serve warm.