Whole or spatchcock chicken work well on
the Kettle but my advice is do not try to cook it too low and slow. It really needs to be smoked at around 280-300 F and it will only take a couple of hours. Cook it too long and it will dry out and 1-2 hours gives chicken more than enough smoke.
When I do chicken like this I take 4 ozs of butter, the grated zest of 2 limes and their juice, 2 crushed garlic cloves and half a habanero chilli chopped finely.
If the butter is cold then grate it into a bowl to soften it and add all of the other ingredients. Mix well with your hands
If you spatchcock the chicken then spread it out breasts up. If you are doing it whole then cook it untrussed as either beer can chicken or with the skin removed from the large end of the cavity to ensure that it remains open.
Lift the skin away from the breasts by poking your fingers underneath and insert 1/3 of the butter mix under the skin of each side of the breast and squish it evenly underneath, Make a small slit in the skin of each thigh and put a little butter under the skin there too.
Rub the rest of the butter under the chicken - on what was the inside of the carcass.
Brush some corn oil over the skin and dust with salt and pepper
Arrange your lit coals on either side of the coal grate with a foil ban between them.
Smoke at _150 C (~300 F) until the internal temperature 80 C (175 F). Wrap in foil and leave to rest for 30 minutes before carving.
You may think that so much chilli would make it very hot but you will find that the heat is absorbed by the skin whereas the lime is absorbed by the meat. You get a lovely contrast of cool meat and very spicy skin.
Some people brine their chickens but I don't any more. I find that it alters the texture of the meat and makes it too wet. It can also make the meat pink even after it is cooked which can put some people off.