I had some luck on amazon and recently reorder watering nipples. I intentionally repurchased the onces I had previously and got a different valve ment for guinea pigs. They like to push in with tongue, rabbits like to chew. I order 2 different replacement sets from 2 different vendors and both for guinea pigs and being advertised as being for rabbits. So I broke down and bought these. There not cheap but they work right. https://www.allthingsbunnies.com/Original-Drinking-Valve-1-8-MPT-p/aws109.htm Into copper tubing . that uses a large pot for a resevior (I place a clear tote over the black pot in winter). I use a very short heat tape (In zone 5).