There are numerous ways to prep fowl for smoking. If its your first bird I would recommend a minimalistic approach. You need to have a stable platform to know what the chickens are before you go off experimenting with brines and rubs and compound butters and injections, etc. Everyone will tell you what they think is best, 10 people 10 ways. Just smoke the chicken, it will be dang tastee believe me. The only thing I would recommend is some suntan lotion, some oil or any oil, just rub the bird down so the skin doesn't break and crack. Maybe salt and pepper on that. Then after you know what the smoke does to the bird have a nother and try a brine or an injection, or compound butter, or any number of of those with different spices, herbs, and veggies!
Experience the smoke with the bird first, so you have a good gauge to judge what all the other modifiers can do.
Oh and take notes. Write down what you do, what you got, what you like and didn't like, and what you want to change and or try the next smoke. The combinations are endless. If you do everything at once you don't know what you'd change or what it did or what you'd change. Set a good base point to start, you will have a delicious chicken with just salt & pepper and smoke.
Of course like the other folks here, its only my opinion and we all know what opinions are like.
Good luck however you go and enjoy the smoke