I did the same thing Christmas. I had roasting hens in the smoker. 225 for about 4 hours, they were not edible

Spatchcock......................I bet I'm not the only one that had to google it.

To achieve chicken with a slow smoked quality and crispy skin takes a lot of work.
What most do is hedge and just cook at 325 the entire way to get crispy skin and a decent amount of smoke while sacrificing the slowly cooked/rendered quality of the meat.

The challenges with chicken include the subcataneous fat and moist skin. You can use olive oil/butter/mayonnaise to achieve some crispy skin, but you have to render the sub Q fat to obtain perfect results.
Several techniques work; including carefully lifting the skin and scraping the sub Q fat off with a knife prior to smoking. Drying out the skin with paper towels and putting the chicken in the fridge uncovered for two hours prior to smoking also help.

As far as temps; slowly rendering the fat at 250 for the first hour, then bumping up to 325 the rest of the way helps.

Scraping off the subcutaneous fat prior to smoking is a ridiculous amount of work, and have only done it for competitions.

At home, drying out the skin with paper towels and then uncovered in fridge for two hours, then smoking at 250 for the first hour in the smoker, then going at 325 in the Big Easy the rest of the way is what I usually do.