I raise rabbits and our pen has way too many spiders to be safe for the rabbits. We have had a couple of otherwise healthy kits(baby rabbits) die and believe it is from the spiders. Our pen seems to have become a haven for black widows and some spider that is a tan color. We've cleaned the pen several times and sprayed some outdoor yard pest control products that was supposed to kill spiders and repel them. Well, they only worked for a couple of weeks and now the spiders are back. I don't want to use too many chemicals since rabbits have sensitive respiratory systems and we have newborn babies frequently. The ultra sonic repellents effect the rabbits like they do mice so they won't work. Any suggestions?