This is the chicken grit feeder from OpenFabPDX originally posted on www.thingiverse.com/thing:4562580 

This mounts with zip ties via built in holes. It has been suggested to flip the lid prior to printing to decrease the need for supports. 

Material: any. However if you will be hanging in sunlight, stick to the UV stable stuff

Infill: standard is fine. However some people have used higher infill to make it heavier.

Support: This needs no supports, but if your material/printer tend to need them, go for it. For PETG you may want a brim to prevent lifting.