What you can try is to de-bone it if you need it smaller to fit in the oven. IF you have never done it practice on some chickens first so you do not ruin it. You will have to alter the cooking time a bit and make sure you tie it properly and test the internal temp right. If you want to let me know I can help.
(I am a executive chef been cooking 20 years)
1. Most common residential stove are big enough for it to fit whole birds that size, if you do have a large one or a commercial oven you can make an aluminum foil tent over it and just use the bottom of a large pan. A residential oven might work by setting the bottom rack to it's lowest position.
2. Cut it in half.
3. Open pit fire.
4. Rent a very large smoker if you don't have one. and smoke it whole.
5. All the BBB we have raised except for the first two, we just cut the meat off, the wing, legs and thighs are not to bad the breast can be a little tricky.
Since we always do option 5 now days, I remove the meat and don't bother removing the insides.
I once cooked a 39 pound turkey. It touched the top of the oven and over cooked there. I would cut it in half for more even cooking. Even better would be to cook the whole breast meat and legs and thighs sparate. Dark meat usually takes a little longer to cook. A whole breast can still make a nice presentation if your making it for Thanksgiving.
last year I did the foil tent in the largest roastin pan I could find
1. it took a week to defrost in fridge
2. add 1/2 bottle of white wine to the swansan broth to bottom of pan for basting
3. cook at 325 for 12 hours, I put mine in the oven at midnight and went to bed, it was done by noon.