agressive behaviour

Question
right now i have 6 cats of my own.  one i am having a major problem with that someone there might be able to help me with.  my cats have come from various places, 1 from a yard sale 1 from the pound, 1 from my work place, 1 from my sisters work place and 2 from my back yard.  the first one was outside for alomst a year.  we fed her and gave her shelter and eventually we were able to lure her inside in the middle of an ice storm in Feb.  we got her declawed and she intergrated into the brood fine.  the other guy was born a year later and spent the summer outside and came in in november and i tried to find a home for him....6 cats is just a lot of cats... i waited to get him declawed and neutered and i finally broke down and in March brought him to the vet after he started spraying around the house.  my problem isn't the spraying we have corrected that behavior but he is agressively pouncing on and biting all my other cats.  they are afraid of him.  he is not intergrating well.  i have tried placing him in a wire dog crate and letting the other cats see him and him see them and he ignores them and they ignore him....so that didn't work, i also tried a harness and leash and he isn't liking that either, he just flops over and plays dead.  

right now he is so agressive he has his own room 8 ft by 9 ft and is let out for 3 hours of run time while i lock up my other cats.

do you have any suggestions on how to get him to stop agressivly pouncing on my other cats?  i don't want to send him away but i can't keep him locked up in a room crying all day either.

HELP!!!!! PLEASE!!!!!!
i'm desperate


Answer
Michele,

There are just some cats that are overwhelmed by the number of cats you have.  Add to this that in some cats declawing seems to induce very aggressive behavior.

What you have not told me is how long has this aggressive behavior been going on? In some cases it takes a cat a couple of months to finally integrate.  There are some cats that never do and need to be in a one cat household.

It sounds to me as if you have done all the right things and he is just not going to fit in.  In the long run, it will be better for everyone, you and all the other cats, if you found him a home where he might be the only cat.

One thing you might try is, if there is one other cat he gets along with, you might try isolating the two of them for a number of weeks and, if they still get along, see if you can add one other to the mix.  

Another option (long shot time), is to try a Feliway diffuser (a pheromone based spray available from most pet supermarkets) in the room he frequents the most and see if it dulls the aggressive tendencies. Along these lines you might try something like prozac (supervised by your vet) to see if that may help.  One caveat on this last is that some cats react to any drug that messes with their heads in the opposite manner than desired since they may try to fight the effects.

I really have no other ideas at this time.

Good luck and best regards... Norm.