I would be killing everyone I saw as well, especially the ones around the prison.
I know Rick said he wanted a bunch still lurking around the fence to make it look like the prison was still overrun and keep strangers away (the bad ones) but wouldn't that keep the people legitimately looking for help away too?
Has Rick totally abandoned his plan to look for other survivors and a safe haven?
He has the safe haven, so...
I just know that it would always be in the back of my mind that the Zombies might find a way in or one of them could potentially bite me or one of my group on the way in or out of the prison.
I would also think that if I killed all the ones around me that it would take days, weeks, months or even years for others to potentially reach me and I would want to deal with them on more of a one on one/two bases instead of a herd.
As far as making new ones... How many new ones could be made with the majority being made in the first days, weeks, months of the outbreak?
How many could be made with the majority consuming any potential new ones? OR
If you are bitten the other survivors "take care of you" either before or after you die.
Don't we see week after week all the abandoned cities that are overrun with zombies?
Aren't we lead to believe that there are only small pockets of survivors left here and there?