Skeptical at first but huge hit!
Ordered a large, and since we have no clue what piggies planks are, was not sure about the very large opening at the top.
Being inventive, my dog adores this and this will be a great introductory frozen feeder for incoming pups.
I first just wrapped the outside with saran wrap and filled with canned or prepared raw grind and popped in freezer.
Lovely frozen block that was more exciting and easier to reach the bottom than a kong. Cannot attest to chewing strength.
Also have popped in a hard boiled, peeled egg, then put an inch of canned tripe in to block the top opening. Covered top with saran wrap, placed upside down on dish and froze.
My dog LOVES this peeled egg cage! First feeder we've been able to try this!
We will probable freeze some sardines flat and do the same. She will love it!