Understanding Biofilms in Chicken Waterers: The Basics

Understanding Biofilms in Chicken Waterers - Chickenmethod.com

Hello again, friendly chicken keepers. If you have ever forgotten to clean the water container for your chickens, you probably noticed that slimy layer forming inside your chicken’s waterer and wondered what in the world is going on. Well, that’s what is called a biofilm, and it’s something you should definitely know about. Today, we will be looking at biofilms—specifically algal and iron biofilms, among others—to help you keep your flock’s water fresh and clean.

What is Biofilm?

First off, let’s talk science for a sec. A biofilm is essentially a community of microorganisms that stick to a surface and produce a slimy film. These can be bacteria, algae, or even fungi.

Biofilms are common in various environments, but today, we’re focusing on those pesky ones that form in your chicken waterers.

Why Should You Care?

You might be thinking, “So what? A little slime never hurt anyone.” But here’s the deal: biofilms can harbor harmful bacteria and other nasties that can compromise your chickens’ health. Plus, nobody wants to drink from a slimy cup, right? Chickens included.

Algae is a pretty green color for the most part and actually takes up nutrients from the water, thus cleaning it in a sense, but the problem is that algae die, and when it does, those nutrients, beneficial or harmful, are released.

If you are wondering what is in the water that your chickens are drinking, you can get it tested at a lab, or you can purchase a home test kit and usually find out very quickly what you have.

Algal Biofilm

Alright, let’s get into the nitty-gritty. Algal biofilm is basically algae gone wild. It forms when algae in the water multiply and stick to the sides of the container. Algae needs water, light, heat, and nutrients to grow, so naturally, warmer seasons see more algal growth than colder seasons do.

Nutrients can get into water naturally or by chickens scratching, pecking, and pooping, among other things.


  • Health risks: Algal biofilms can contain harmful bacteria. The problem is that the algae concentrate these pollutants.
  • Water quality: It can make the water taste and smell bad, leading to decreased water intake for your chickens, which is not healthful for your flock while decreasing egg production.

Prevention and Treatment:

  • Regular cleaning: A good scrubbing can go a long way toward keeping algae away. I use a carwashing mitt that is worn like a glove. I can get in there and really clean the entire waterer in seconds.
  • Use waterers that are solid colored and won’t let light into the container, like galvanized waterers.
  • Use of algaecides: Make sure they’re safe for animal consumption. Algae don’t like copper, so if you put a small piece of copper pipe in your water dish, it will help inhibit algal growth,

Cutting a piece of copper pipe - Chickenmethod.com

It doesn’t require much effort to polish an old piece of copper to put in your waterer.

But let’s be clear. Changing the water in your waterer every day and cleaning it often is by far the best way to keep algae from flourishing in your chickens’ drinking water.

Iron Biofilm

Next up is iron biofilm. This one is a result of iron particles in the water sticking to the container’s surface. The ingredients necessary for this film’s growth are dissolved iron, which can come from iron pipe or from hard water, a slow water supply, and a rough surface. Temperatures best for iron biofilm growth lie between the 40s and the 70s Fahrenheit.

Iron biofilm will likely be found in basins in an inline trickle system that is well-fed or spring-fed. Growing well in the dark, this will likely be inside a coop or structure protected from sunlight. A dark galvanized waterer can partially oxidize, creating a rough surface where microbes can hide and further build-up can occur.


  • Health risks: While iron is generally less harmful, too much of it isn’t good either.
  • Water quality: Iron biofilm can give the water a metallic taste.

Prevention and Treatment:

  • Filter your water: This can help remove excess iron.
  • Regular cleaning: Again, scrubbing is your friend here.


Iron and other minerals can build up on the inside of pipes even as water flows through them, especially in very hard water.

Hard water, by the way, is water high in mineral content.

This scale creates an area conducive to further biofilm accumulation as the surface roughens and pits and cracks. The ensuing biofilm will harbor good and bad elements, some of which can make your chickens sick.

At least three unwanted events occur from scale build-up.

The red, slimy build-up that is primarily iron can make water unpalatable to chickens. Scale can break off and clog orifices in waterers, valves, and pipes. Colonies of pathogenic (disease-carrying) bacteria can grow in the environment provided by scale. These bacteria can cause massive outbreaks of disease in a flock.

The only way to eliminate scale is by scrubbing waterers regularly, aka preventive maintenance.

Other Types of Biofilms

There are also bacterial biofilms and organic matter biofilms that can form, but they’re less common in well-maintained waterers. Any additive to a chicken’s drinking water will probably create some sort of film, including sugars, medications, and vitamins.

Again, clean your waterers regularly, and you won’t have a problem.

Prevention and Treatment

The key to preventing any biofilm is regular cleaning. Use cleaning agents that are non-toxic and safe for chickens. And don’t forget to scrub all the nooks and crannies!


  • How often should I clean the waterers? At least once a week, but more often in hot weather.
  • Can biofilms make my chickens sick? Yes, they can harbor harmful bacteria.
  • What are the signs of contaminated water? Look out for changes in water color, smell, or a decrease in water consumption.

Biofilms might sound like something out of a sci-fi movie, but they’re very real and can be a real pain in the feathers. The good news is with regular cleaning and maintenance, you can keep your chicken waterers biofilm-free. There are lots of things you can do to keep your flock healthy. Practice the essentials to keep those eggs rolling in.

As always, I appreciate you taking the time to read my blog. If you are inclined to leave a comment, please do so below.



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