I use the galvanized metal waterers in most of the pens, but like to have a few of the 1-gallon plastic ones on hand to use when needed. The Fla sun is very harsh on the plastic, and causes it to crack. I have a few that only have a crack on the top. Is there anything I could apply over the crack that would seal it? I've tried my trusty duct tape, but even that doesn't give a really good water/air proof seal. Once air can get in through the top, the water comes pouring out the bottom. I'm thinking there is some kind of silicone sealant in a tube that I could squeeze over the crack which would hold it tight once it dried. It would also have to be non-toxic so it wouldn't contaminate the water for the chickens. Please share your advice. My thirsty birds & I all thank you!