Well the question is probably moot. I let the chickens sit for 4 hours and just stuck the probe in and the breast temp is 116.
I was using a brine recipe from a book and it suggested a low temp for a while and then higher. However, since chicken needs to be 160-170 then a 140 temp will never get it there. I was getting a little smoke but not much.
I just raised the temp to 225 so we'll watch the probe temp and see how it goes.