Wire with squares in it as flooring– can you specify if this is all wiring grid, or there’s some solid floor for your rabbit?
I think it’d take a while for any rabbit to acclimate to a larger, “cave” environment, especially if it still has chicken scent. I’d double check it’s all clean (I use diluted vinegar spray for wood). It may help to rub a few small towels on your rabbit to pick up scent, then put them in some locations around the place so it seems more like his territory; I did this with Wick’s carrier and he loves it.
I’d give him more time. I’m quite terrible at spacial visualization, so I’m not sure of the layout (you described it very well, I’m just bad), but make sure there are some books and crannies your rabbit will feel safe in. Sometimes a large house has no hidey spots for his security!
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.