From: Jeffrey White <jrwhite@...>
I recently purchased a copy of the IC Rules for Receipt,
Handling, Stowing, Bracing and Delivery of Less then
Carload Freight Issued in Feb 38 and revised in Oct of 49. 
There are two illustrations of methods of blocking car
doors open to provide for ventilation one for a wood door
car and one for a steel door car.
I am guessing that they were hauling livestock like crated
poultry. I never heard of using a closed car for this before.

I've got four photos of this sort of thing: prize heifers being unloaded from a Wabash steel auto box into a DC-3; a giragge being loaded into a Pennsy X31, a giraffe being loaded into an ACL auto box, and zebras being loaded into an unknown boxcar.

So while it probably wasn't common, it wasn't unheard of, especially for specialty animal moves.

Ray Breyer
Elgin, IL