what temp are you cooking at how long did it take to get chicken done and how much wood did you use sounds like you used to much wood to smoke the chicken and cooked to long i use a coffee can full of wood and that is all when wood is burned i dont add anymore just let it cook till temp of chicken reaches 170 hope this helps
All I can add is this....Maybe open up the vent.
The smoke is supossed to move over the chicken and out of the smoker.
If you have too much smoke holding in the smoker you get creosote building up and that's not good.
Let the smoke gently stroke that bird and then be on its way.
That's my 2 cents hope it helps and good smokin with ya
Ditto's on the above replies. Be sure and use a temp probe in the chicken and pull off at 170. Also, try about 225 - 230 on temp. You may also want to try brining the chick first. It will help pull moisture and flavoring into the meat before you start smoking it.
Below is pic of a chicken I did not long ago and brined it. Sure was tasty.