To see how crazy the HD can be, when I was putting in the restaurant they were concerned about cooking in the OH (the OH was under a steel roof) and taking the food out of the OH and bringing it to the kitchen because a bird might do it's business on the food tray. Since the OH was on an outdoor patio and the food came to the customers on plates to the patio I asked them what to do about the customers food when we served it. They were not worried about customers getting their food contaminated but were concerned that I make sure the food coming out of the smoker was covered on it's way to the kitchen. It took a while for them to agree to let me put the smoked food in a cooler and cover the cooler with a towel that could be thrown away if the bird did it's duty on the towel. Not good enough to clean off the top of the cooler!! So far, no bird problems.