3D Printing for Chickens (Feeders and Other Accessories)

FDM Printers, Slicers, and Filament​

There are a number of different processes and categories of equipment that fall under the broad umbrella term of “3D printing.” From the standpoint of entry/hobby-level equipment for the average consumer, there are two main categories of 3D printers: filament deposition modeling (FDM) printers and resin printers. This article and its associated functional projects are for FDM printers only. Do not use a resin printer to make functional objects that will be in contact with chickens or other animals – the materials are potentially hazardous.

FDM printers work by melting plastic filament and extruding it into a new shape. The input filament is typically mounted on a large reel and feeds into the print head. The print head moves around and builds up an object one 2D layer at a time, where each of those layers has some small thickness to it. Each layer is produced much like you would draw the corresponding shape: laying down a perimeter, also called a wall, and then drawing lots of little lines to fill in larger areas. The furious scribbling inside the perimeter is called infill. The more infill, the more material required and the more solid the object.

The object being printed is initially represented as a digital 3D model, usually a file ending in .stl. These files contain maps of vertices and edges defining a mesh for the exterior of the object, but the printer needs to know how to build that mesh’s shape in terms of horizontal layers. This is where a piece of software called a slicer comes in. There are a number of freely available slicer apps: Prusa Slicer, Orca Slicer, and Cura to name a few. Some brands also have their own slicer programs specifically tailored to their machines. As the name implies, a slicer “cuts” the mesh into a lot of thin layers and produces machine instructions for how to print each layer. For FDM printers, the resulting instructions are printer-specific and saved as a .gcode file. Slicers typically offer a variety of settings to change the quality and internal structure of the print. Slicers also have the ability to add extra structures called supports, which are necessary if you have difficult-to-print structures like large overhangs where the filament may otherwise collapse. All of the projects attached to this article are support-free, meaning they don’t require supports to print well in their default orientations.

There are many types of filament for FDM printers. Only use a food-safe type of filament like PLA or PETG for anything that will be in contact with chickens or other animals. PLA is the easiest material to print with, but PETG is supposedly more resilient for outdoor usage. Both PLA and PETG are relatively safe to print inside a home; other materials can create quite hazardous fumes during printing. Clear PLA and PETG are both safe for use with chickens, and most plain colors of those materials are too. Avoid special/fancy filaments like PLA+ or silk PLA for use with chickens or other animals. Also avoid filaments that have inclusions of other materials (wood, glow-in-the-dark compounds, glitter, etc.).

Air quality caution: print only in a well-ventilated area, even when using a relatively safe material like PLA or PETG. Do not use an open-air printer or one that vents directly into the room for any significant length of time without at least partially opening a window nearby. VOCs and CO2 can both build up quite rapidly in a completely closed room with an active printer (something the author has directly tested with a CO2/VOC meter). If you are unsure how effective your ventilation is, you can buy a portable CO2/VOC meter to monitor the air quality in or just outside the room. Never print in a room with pets. Use caution in proximity to birds and aquariums, even if they are not in the same room as the printer.


Other things you may be wondering (FAQ):

• Why are resin prints potentially hazardous for chickens? Consumer-grade 3D printing resins are not considered a food-safe material even when cured. Resin printers are great for printing highly detailed ornamental models, but they should never be used to print objects that animals will be in regular contact with or objects for use with food/water. Some resins claim they are safer by being "plant based" or simply "low VC"; while some of those products can indeed produce fewer VOCs in their liquid state, the lack of safety with food and water remains even for the cured product.
• Do I need an expensive machine to print useful things / the designs in the ZIP? No, although to some degree it depends on what you consider “expensive.” All you need is an entry-level machine with a big enough build plate. Suitable machines range from around $200 to $500 at the time this article was written. Some 3D printers get significantly more expensive, such as $1,000+. Those printers have perks for sure, but you don’t need anything in those upper price brackets to start making useful items. Really the only category of printer to avoid are those with exceptionally small build plates (there are some super-tiny printers on the market aimed purely at making small toys/trinkets).
• Is my FDM printer build plate / print volume big enough for the projects in the ZIP file? To print support-free, the biggest projects here require a build plate of at least 220mm x 180mm and a printable height of 200mm high (or 8.7” x 7.1” x 7.9” in inches). The feed scoop is the tallest design (200mm), and the double grit holder is the widest/deepest (220x180mm). A build volume of 180 x 180 x 180mm will be able manage a few of the projects, but a build volume of 220 x 220 x 220mm is better. You can try reorienting projects to fit on smaller build plates, but changing the orientation may significantly decrease the quality of the print and may require the use of supports (all of the designs are support-free in their default orientations). Not all projects scale up/down well; this is noted per-project.
• What printer/filament/slicer did the author use to make the example prints? I used an Anycubic Kobra 2 Plus with a 0.4mm nozzle, various non-toxic, solid-color Sunlu PLA filaments (clear, white, etc.), and a single reel Sunlu filament dryer. This printer has a 300x300x350mm build volume. All pieces of equipment used are very much budget, entry-level options for medium-sized FDM printing. This should only be considered a point of reference only, not a product recommendation. I used both Prusa Slicer and Anycubic’s own slicer; both slicers are free.
• What makes one design “easy” to print while another is “difficult?” Different combinations of models, particular printers, and filaments require different slicer settings for parameters like print head acceleration/speed, temperature, fan activity, and so on. A model is “easy” if the default settings for the filament/printer in the slicer are likely to work just fine for the intended purpose of the model, and if small imperfections in the finished result won’t harm its utility. Another model will be “difficult” if the settings have to be tuned more carefully to the particular printer, filament, and model.
• Do I need to do any post-processing on my prints to make them safe for chickens? Potentially. You may have excess material that needs removal, such as stabilization brims at the bottom that don’t tear away easily, globs from the print head starting a new layer, rough edges, or even edges or corners that end up a bit sharp. A hobby/utility knife can be used to remove excess material like brims and to clean up or smooth edges. A deburring tool can also remove brims and smooth edges and is somewhat safer to use than a knife (although not entirely safe – you can still drive a deburring tool’s blade right into your finger!). Sanding is also an option to smooth layer lines at edges. Use caution with any kind of electric sander or rotary tool – both have the potential to melt the plastic and easily destroy the outer wall.
• How can I clean 3D printed feeders/waterers? First, try to minimize porosity in your prints with settings in your slicer. Smooth surfaces and minimal gaps into inner portions of the model are very important to create an easily cleanable surface even if it has a texture (which nearly all 3D prints will – some texture is unavoidable without post-processing use of fillers and/or sanding). Smooth top layers with no gaps and excellent layer-to-layer adhesion will minimize porosity. Second, if you can simply wipe it clean with a damp cloth, that is ideal. For more thorough cleaning, printed parts can be hand-cleaned with soap, water, and a soft sponge. Avoid fully submerging the part if you used <100% infill. Avoid abrasive scrubbers that may leave scratches. Let feeder parts air dry VERY thoroughly before putting them to use again with feed. Avoid putting your prints in the dishwasher, since the heat from a hot wash or drying cycle has the potential to warp the more commonly used materials (particularly PLA).
• Isn't PLA biodegradable / not UV-resistant / not heat-resistant? PLA is only biodegradable under very specific conditions - don't throw it in your compost pile and hope that it will decompose. This means it also won't break down rapidly due to being in a chicken run. The outdoor resiliency of PLA is a subject of some debate on the internet. Most of the complaints about it are centered around color fade, and long-term toughness tests often subject the object to some kind of serious falling damage that isn't really normal usage. Many plastics eventually become brittle when sitting in high heat and direct sun for a long time. The longevity of your print will depend a lot on the conditions it is exposed to. To maximize the lifespan of any 3D printed object, it's best to keep it out of direct sunlight and also not leave it sitting in intense heat. PETG is a bit more heat resistant and supposedly more UV-resistant too, but also significantly harder to print. Both materials can warp if exposed to very high heat, such as in a hot car in the sun or in a heated dishwasher - neither of which is comparable to the conditions of a chicken run.