We used a ton of old cedar to make our banty shanty- but it was an old fence that had been weathered for years.
I have some old cedar forming parts of my nest battery (hate using that word...how about wall-o'-nests?) and it's been fine. It's not getting wet, it's had years to evaporate fumes, and it's dry and practically petrified...I think it's good for resisting bugs.
I've read lots of arguments on how pine is bad, cedar is bad...I use hay for bedding so it's not like the girls even touch the wood, and they're certainly not closed up in the boxes...
I think just using your judgment is fine, being aware that the aromatic wood is not appropriate, but it's fine if it's not giving off fumes or oils.