Like I've said already, they are just living some pipe-dream. They have never tried farming and don't know the first thing about it. They have delusions that they can grow all they need to eat for a year on a piece of land smaller than a football field. It's quite ridiculous.
However, you only need grains for the chickens in the winter if you allow them to graze (which requires about 1/4 acre all together depending on how many chickens). So a small field of corn would suffice if that was all you used it for.
Rabbits are actually a very good resource. You keep them caged and they breed like hell but you need feed for them of course. The good thing about rabbits is they take up small space. The bad things is you have to feed them and figure out if the food you give them is worth the meat you get back. It generally is. Plus you get fur.