Having lived my life near mega-cities, I went to Wikipedia to learn what a corn crib might be:
http://en.wikipedia.org/wiki/Corn_crib You must have another meaning in mind
Whatever you're considering, be cautious about aspergillus. Corn is considered second only to peanuts as a cause of aspergillosis in our parrots. The high liquid content in corn combines with the heat and limited ventilation of storage bins to grow the aspergillus fungus. It's invisible and deadly. In this country, human-grade food products are tested for acceptable levels of aspergillus before sale, but if you're letting your birds play in a "crib" in which corn has been stored, you could be inviting tragedy.
If OTOH, you're thinking of building a slatted corn crib lookalike for your birds to play in and gnaw to splinters, be careful to use only bird-safe materials -- untreated wood from safe trees, fasteners of a metal that is safe -- and build in ways that don't trap birdie body parts. Not a task I would undertake for many reasons. Also, be mindful that any playhouse could look like a nest cavity to sexually mature birds. If you're breeding and want eggs, not so bad. If not, you might want to reconsider.
Just my first-blush thoughts
