Regarding water quality testing. Do you test water pH and/or hardness, and can you give us a picture of the normal ranges you see in the samples you collect?
Changing litter depends on the situation. In Mississippi, poultry growers go for years and never change the litter unless there is a disease problem or other issue that may require changing it. Growers remove a certain amount of litter when it gets too deep in the house and then even back out what remains and keep growing birds. Some growers have gone 8-10 years and never totally cleaned out to the floor and replaced litter with new bedding. In Arkansas, where I grew up, many growers clean out to the floor once each year and replace the old litter with new bedding material (pine shavings, rice hulls, etc.). So again, it depends on the situation and what the company that owns the birds is asking of their contract growers.
For removing Biofilm from water pipelines, has anybody tried enzyme based detergent that can very effectively dissolve the Extracellular Polymeric Substance (EPS) or the protective matrix of biofilms, further sanitization actually removes the complete biofilm and renders the water safe for birds?