Summary

Here's a great rainy day project for the family - 3D print a suet feeder for the birds and make suet cakes.
Printing: The feeder is printed in 5 pieces: frame_right, frame_left, 2xhinge_pin and a roof. Print the frames with the cross bars on the print bed and include support. Print the hinge pins with the pointed end up. Print the roof on edge, as shown in the photo. Best to print the frame and hinge pins in PETG and the roof in ASA for greater durability, but all parts in PLA will also work.
Assembly: Put the two frame parts together so that the hinges overlap and the nubs on one frame fit into the holes on the other. Insert the hinge pins with the points toward the middle; they should snap into place. Put a length of string on the roof to make a loop between the rings. Place a suet cake into the frame, close it and slide into the dovetail slot in the roof.
Making suet cakes: Follow the directions from the Audubon website https://www.audubon.org/magazine/make-your-own-suet
Note that you should only provide suet for birds when it's cold outside (near or below freezing) and only in an enclosed feeder like this to prevent birds from getting the fat/oil on their feathers. Greasy feathers do not provide insulation that is needed for the birds to stay warm. Also, the audubon recipe recommends vegetable shortening, but other sites recommend only using true beef suet, which melts at a higher temperature. See https://www.nativebirdcare.org/blog/killing-songbirds-with-fats-suet-pb. Files are included (suetcakeform.stl and formpress.stl) for pressing the suet mixture into cakes that fit this feeder. These can be printed with PLA or PETG, no support needed. The audubon recipe makes 3 cakes in this form. Store, wrapped in waxed paper in the freezer until use.