The CrumbleHopper™

A dietary issue

A colleague approached me a few weeks ago about a laboratory mouse feeder. She was having an issue with one of her experiments; she knew I had done some 3D printing and thought I might be able to provide a solution. Her problem was that she was feeding her mice a special, but very crumbly, diet.

The crumbly diet was making it impossible for her to monitor caloric intake using our currently available food hoppers. Depending on the type of hopper, either the food would crumble all over the cage bottom, or the mice would kick bedding up in with the food and make any accurate food measurement impossible. What she needed was a laboratory mouse feeder that was up to the task.

Designing a mouse feeder

So, my colleague asked me to design and produce a small food hopper that could hold crumbly food without losing it, while still allowing the mice easy access to eat without being able to kick bedding in. It was also important that the hopper be easily added or removed from the cage to allow daily weighing of the food. And as the planned experiment involved some 40-odd animals, they really needed to be low maintenance, and quick and easy to use.

Based on the cages that we have in our animal facility (pretty standard IVC’s from Tecniplast1), I figured the most obvious solution would be to have a hopper that you could hang off the metal grill hopper already present in the cage. Then it would be easily removable as well as being elevated off the floor, and it would be a simple matter to design it to be an easily munchable height from the cage floor.

I “borrowed” a cage from the facility to measure up, and designed what is essentially a hanging basket with hooks. Then after a suggestion from my colleague I made a few variants with different size/shape holes for the mice to access the food:

Initial designs for a laboratory mouse feeder.

Improving the design

I printed these 3 prototypes and gave them to my colleague to test out on the mice. She obviously monitored them very closely, and found that the mice would happily eat from any of them. She did, however, find that the supporting struts were a bit flimsy, so I strengthened those.

Of the three designs, she liked the vertical rectangular slits the best, but wanted the holes slightly wider to allow better access for mouse nom-noms. So, along with a slight adjustment to the height of the hooks to give better attachment, I present the final version of my laboratory mouse feeder, the CrumbleHopper™:

The Crumblehopper: a handy laboratory mouse feeder.

I actually quite enjoyed trying to make these for my colleague, and it does seem to fulfil an otherwise unmet need. So to that end, I am setting myself a couple of goals:

  • To keep an eye open for other experimental situations that could do with having an improved piece of kit. I already have a couple in mind that I am working to produce a solution for.
  • I hope these pieces of lab kit I am developing will be useful to people outside my lab, so to that end I am working towards setting up a small shop on this website to sell the things at a reasonable cost. Where I can, I will also make the designs available online so people with access to 3D printers and such can make them themselves.

Finally, if any of my loyal readers have a niggling problem that could be solved with a relatively straightforward (but otherwise non-existent) solution, please contact me and maybe I can design a solution, as I did for my colleague.


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