Thanks for all of the replies.
I spoke with the AHJ and he said conduit up to about 6' and UF above 6'. All of the enclosures need to be weatherproof. He also said there is a 1/2" romex connector that is waterproof. It looks like a SEU meterbase connector. My supplier is looking for one now.
If I find one I will post it here.
Best To All,
They are nothing more than a cord grip with a elliptical instead of a round opening in the rubber grommet. Most manufacturers of cord grips also have these. It is more of a UF grip instead of a NM grip. What is the point of a watertight NM grip when NM is not allowed in wet locations?
Weatherproof is too general of a term. Type 3R enclosures are commonly considered weatherproof but are not acceptable in this environment. 547.5 C requires enclosures to be resistant to entrance of dust, be suitable for wet or damp locations, and be suitable for corrosive environments if any of these conditions will be encountered - in a poultry building they are all conditions that will be there. The corrosive environment will even get to things installed in a separate mechanical room - not as quickly but it will eventually get to things.
My best suggestion is to put breaker panels, ventilation, feed and water controllers, etc either on exterior of building or in a separate mechanical room. Even if they designed for the environment they will still last longer if you keep them out of it.
If you do run any PVC don't forget about expansion joints. Runs in these buildings can be quite long sometimes and can encounter a pretty big temperature change from unoccupied temperature in winter months to occupied temperature in summer months.
The only likely thing below 6 feet of the floor is the supply to feed motors and this will likely be flexible cord because the feed lines are raised and lowered depending on size of birds and raised as high as possible when unoccupied to make cleaning litter easier. The cord is either pre-installed or included to be field installed and has a protector on the first few feet that are in proximity to the birds.