Laser-Cut Automatic Chicken Feeder

In my chicken coop, these tiny, annoying birds called starlings eat more chicken food than my chickens. My goal with this project was to create a chicken feeder that allows chickens to eat food, but prevents starlings. Devices like this already exist, but they're expensive, and my goal is to create something cheap. I also wanted to keep it purely mechanical, as I live in Vermont, and electric components don't do well in the snow. The chicken feeder uses a pressure plate that uses the chicken's weight to open the lid, allowing them to eat. The lid closes itself after the chicken leaves.

One goal of my project was to use relatively few and cheap materials. It requires:

1. 0.2-inch thick plywood cut to the above dimensions
2. An SVG file is linked to laser cut the plywood
3. 1 or 2 hinges
4. Super glue and accelerant
5. You can use another glue if you're very patient
6. Graphite lubricant (optional)
7. Low resistance spring ~1 inch long
8. Ensure the spring will fully compress when your chicken stands on it.
9. Square wooden dowel (any diameter)
10. Any two objects the width of the fully compressed spring (optional)

Tools needed:

1. Laser cutter
2. You can cut it by hand if you really want to, but I recommend not
3. Anything that can cut a wooden dowel

Links to STL file for laser cutting and PNG files with dimensions:

1. STL dimensions
2. PNG dimensions
3. SVG file to laser cut

Superglue the bottom, one side, and the front panel together as shown. Glue a spring to the bottom panel, centered on the far end. Then add spacers to either side of the spring to prevent the pressure plate from rocking while compressed.

Fit the pressure plate between the side panels, then add graphite if available for lubricant. Glue the middle panel between the side panels, then glue the inner side panels parallel to the outer ones. Finally, glue the inner bottom panel at any height; it doesn't really matter.

Place the back panel on the feeder, but do not glue it. Mark where the inner side panels make contact with it, then remove the back panel. Glue the small inner panels to the back panel so that they line up with the line and are flush with the inner panels when the back panel is attached to the feeder (second image). Remove the back panel, then glue an approximately 3-inch segment of the wooden dowel a little more than one dowel width away from the inner side panels. Put the back panel back on, then make sure you can fit a second wooden dowel between the wooden dowel just glued and the inner side panel before gluing the back panel to the feeder.

Glue the big inner panel between the side panel and the inner side panel so that it is barely not touching the wooden dowel glued earlier (for spacing purposes) on both sides. Then add a 6-inch-long segment of the wooden dowel into the new hole. When you press down onto the pressure plate, the dowel you just added should extend.

Attach the hinge(s) to the back panel, then attach the lid to the hinge. The lid should open when you push down on the pressure plate.

I originally designed my feeder to use a hydraulic system to open the lid, but there was far too much friction for it to work effectively. It took far more than five pounds of force to extend the plunger. If somebody could modify my design to get a hydraulic system to work, that would be amazing. You could also maybe add a hopper to refill the food automatically.