Cat choosing not to use litter box!

Hi John, thanks for your question, pooping outside the box is quite a common problem.  Your kitty is trying to communicate something to you.  Sometimes this behavior can be triggered by the slightest change and quickly become a bad habit.  Here are some basic guidelines for more than one cat households or ones with soiling problems;

• One more box than cat (you need 3)
• Use a plain, non clumping litter with little or no odor control, some cats find odor control offensive.  Use baking soda in the bottom of the box for odor control.
• Scoop often, do not stir litter after or when adding extra litter.  Most cats will pee in one corner and poop in the other.  When you stir, you mix the odors.
• No plastic liners or hoods, access needs to be as easy as possible.
• Location of boxes; one per level of house if possible and not next to noisy appliances like the furnace that may kick in while the cat is in the box and make it scary.
• Never take the cat to the box and deposit her in it.  She will make a negative association.  She must go on her own four feet. 
• When cleaning entire box, do not use anything but a mild dish soap and hot water and rinse well.  Again, the odors of cleaners can cause an aversion to the box.
• Clean the soiled area in the living room with a product designed for cat urine removal, no ammonia products. 
• Cover the soiled area with an object (furniture or something) that prevents cat from returning to that spot.  You can also use double sided clear tape or place a food dish there.  Whenever possible, close off area.
• Spend some extra time playing with, patting or brushing your kitty.

I understand how frustrating this issue can be but try not to let the cat see that  pooping on the rug brings her more attention even if it is negative.  You can also try reintroducing the litter box by taking a really special treat like Tuna juice and leading the cat from the kitchen to the litter box (each box), have her step in the box, out of the box and place the treat down in front of the box.  What you are doing is reinforcing the litter box is a nice place to be.  Twice a day for 5 to 7 days usually does the trick.  Meanwhile the other kitty may want to be in another room for a few minutes while you are doing this.  Good luck!