I recently had a national known company place a fence like structure around the bottom of my deck to keep rabbits from using it as a nesting area. The fencing has a 1 1/4" space between the vertical bars of the fence. Newly born rabbits have no trouble going in and out between the vertical bars. While that is not surprising, I would like to know how small the gap needs to be to keep rabbits of breeding age out from under the deck. Thank you for your time in answering my question.