Ken-- You and anyone else can do whatever you want. But the notion that poultry must be below for safety reasons is a myth, one especially common in Q circles. Repetition of a fallacy does not make it true. Poultry must be assumed to be contaminated but it is science-based reasoning and logic that will provide answers to questions like these; unfortunate that these traits often get replaced by unfounded fears and squeemishness where poultry is concerned. How many times have I heard some insist that 'better' safety is achieved by cooking chicken under another meat yet prep their chicken by washing it or temp for safety using an analog therm, both far more potentially dangerous than cooking chicken over another meat.
Shawn-- Kill temps are lower than typical cooktemps and kill is instantaneous starting in the 160s so the likelihood of drippings coming off the poultry, passing through the air, and landing on the surface of the meat below without being pasteurized is hghly unlikely. However, one could probably make a case for some sort of cut-off point. Support for the position is thin in all but the lowest of low/slow scenarios but a case a could be made, especially with other odd variables--say, the meat going on top was pulled from the fridge cold, the lid rekeased the heat so that ambient temps in the cooker plunged, the lower meat was removed rather quickly after the upper was put on, and so forth.
Illnesses caused by Salmonella and Campylobacter (the two biggies, poultry-wise) are rarely caused by undercooked chicken as most people tend to overcook chicken (fear of 'red around the bone'--another myth!--might be at play here sometimes). Instead they are most often caused by cross contamination that occurs prior to cooking: washing poultry in the sink, reusing the cutting board or plate the raw chicken was prepped on, handling other foods or utensils, or touching other surfaces after hasndling the chicken, etc.
Joe-- The chefs and the 'chefs' on the Food Network can be pretty clueless if not, perhaps, as egregious.
