IMHO you would not want to use the shavings/chips from a Christmas tree. The moisture content (and sap) would be much, much higher than that of the shavings you buy at your feed store. The lumber they use to make the store bought shavings has been dried (usually kiln dried) and has a much lower moisture content. My fear would be your shavings/chips sticking to your feathered friends due to the sap content. Now, if you have a way to dry the shavings/chips before use...then I think it's brilliant! But, again IMHO...I think your gonna have a lot of sap. Let us know how it works out. There was a tree lot own the road from the house this year, apparently they did not have a very good year judging from all the trees that were left over. Sure seems like a waste...I hope someone like yourself comes up with a creative way to utilize them. It's sad if they end up in the landfill.