Hi Avi, there is an "under cover" section of the forum which might be more suitable for your questions?

I guess what you are talking about is a polytunnel. I don't know how you would estimate yield - I guess work out the number of plants you can fit in the space available and get an estimated yield per plant?

The minimum feasible area for veg depends on what and how much you want to grow! Can obviously grow a few bits for the family in whatever size you like but I would imagine if you are thinking more on a farm scale it would be a bit different!

Barn / battery for chickens is to do with how much space and freedom of movement the chickens have, rather than what kind of building they are kept in. I personally wouldn't even think of keeping chickens in a greenhouse, especially not in Israel - it would be far too hot for them, I can't imagine they would even survive the sort of temperature you would get even in a very well ventilated greenhouse / polytunnel, let alone anything else.

__________________
Warning: I have a dangerous tendency to act like I know what I'm talking about.