In my UDS experience, KF Blue loves to cruise at 225-240 no matter what the vents are set to. It simply doesn't do high temps very well. Lump will maintain higher temps a lot easier.
I gotta ask, why would you want to cook poultry at such a low temp anyways? Ignoring the rubber skin result, poultry always turns out juicier and more moist cooking at temps of 325-375 for me.
When you put a huge mass of cold meat in the cooker, the temp will drop a bit anyways. Most folks will get their cooker stable at a slightly higher than desired temp before dropping the meat in to allow for that mass of cold meat.
Modded Brinkmann Gourmet. Basic UDS. Rescued 22.5" OTS. SJS Mini-WSM. Stubbs. B&B Oak Lump.
Cannondale 2009 F8 (for burning off all the great BBQ)