I wanted to share info i have found first hand to be very helpful in a mutiple cat household(FWI alot of this i got from..my cat from hell on Animal Planet)i have 7 cats living here all fixed we have 7 litter boxes scooped daily 2 large floor to celing cat trees ,one so the cats can reach o shelf above our window about 6ft long...and toys and frillys hanging all over,gates so the cats have access where the dogs dont so if they dont want to be around then they dont have to(but they all love the dogs)Still i have problems with attitudes and potty problems once in a while,so...I realise from learning i need more enrichment for them..we are putting in an outside screened area accesiable thru our bathroom window with tunnels to 2 other areas...Also we are incorpating the HUGE size round PVC to go around the top of our celings with coke can size holes every 5 ft..we will put the sticky carpet tiles in the inside for them..and we are making 2 window boxes plus the sun room...this will be wonderful enrichment for them and keep the attitudes in check..I love my cats as much as my dogs and birds and i need to understand their needs also..