You can leave them whole or spatchcock.
Spatchcocking allows for more even cooking of the whole bird not to mention the skin.
They will also cook quicker, as easy as turning up the heat.
Dry brine with a mix of baking powder and salt in a 1:3 or 1:4 ratio.
Air dry the bird in the fridge for 12-24hrs.
A light coat of oil on skin before or during cooking is okay, as is applying a rub.
Cook at 275° or higher, I smoke poultry at 350°-375°.
When straight smoking you're never going to get 'Really' crispy crunchy poultry skin.
But you can get a very nice crisp 'Pop!' on the bite through
For the 'Real' crispy crunchy you'll need to finish the smoked bird or do the whole cook with more of a direct heat source, grill, rotisserie, oven or broiler to completely render the fat out.