Dan,
Let's work through this. First, tell me your programming for each step, and what was your setup. Also, are you absolutely certain the chicken wasn't up against the box temp probe? (you'd be amazed how many times this has happened, and has even happened to me).
Next, I assume (from the sounds of it) you were not home during this smoke? Personally, I'm all about Lazy Q, but I never leave the house during a smoke; it is an electric appliance, and some monitoring is the prudent thing to do. Not meaning to get on a soapbox, just trying to determine what went haywire, and when.
If you will answer these questions, we can go from there. What we may want to do, later, is an autotune. The factory PID settings are generally good, but I've seen a few occasions where they need to be adjusted.
One step at a time, brother! We'll get off that ledge together!