I want to build a nipple waterer system for 4 hens. All of the designs I've seen use PVC - 5 gallon buckets and pipes. I'm not so happy about using PVC to store water that enters my food supply, eventually. (We have switched all our human food/water containers to glass or stainless.) Especially in the winter, when I hop to use a submersible bucket heater to keep the water from freezing, and might have some warm-ish pvc in contact with the water. However, I want to put apple cider vinegar into the water, so I can't use galvanized or copper, right? I was wondering about silicone, but there comes a point where I can't justify the cost. Any suggestions for a better material for water supply?