Maybe an account was set up at the lumber yard? Maybe the builder took a deposit and will bill later? IDK. It does seem odd all the way around and I agree PICS.Yeah......it would be odd to use AS a floor with that being totally out of the norm to do instead of the usual plywood.
Also odd would be to have enough of them to create a floor when they were purchased to use as roosts.
Has me scratching my head and wanting pics.