Since Pamela asked about how much Max weighs and wood slices, I thought that might be a nice segue to these videos:
Note that Max does not always want to chew on wood!
Max weighs around 340 grams. She weighed around 300 grams for years, but once she started flying and building up muscle, she gained. I might note that this time frame also coincides with her increased cheese consumption, as she was then able to fly over and find it instead of waiting for the rare times it was offered. Hmmmm.....
However, my caiques, who are in the 160 gram range, and my former budgie, Ethel (should have been around 30 grams but was around 60 grams due to a HUGE tumor) also love/loved chipping wood.
I just make the slices a bit smaller for the smaller/daintier birds. We have two sizes of wood slices in our house -- large for Rocky/Stella (about 3/8 inch thick) and small for Max and the caiques (less than 1/4 inch). Ethel used to peel the tiniest chunks off of the wood -- a wood slice that lasts Rocky 1 minute would last her six months.
Boxes are also a big favorite around here! Balsa wood would get way too expensive. Max occasionally gets some as a treat. It is quite possible that Harley is too dainty for wood, though. He seems the proper gentleman, unlike my destroyers!