Behavior of older cat

Question
I have a 12-year-old cat that has never given me any problems.  He is basically an outdoor cat, he rarely uses a litter box.  About 5 days ago I discovered that he had defecated on the floor of my bathroom.  Yesterday, he did it again, right in front of me.  Soon after, he went into another bathroom and urinated on the rug.  He has always "asked" to go outside to do his "business" so this behavior really surprised me.  In fact, after the second defecation, I went to put him outside, but he did not want to go.  Other facts that may or may not be related:  Last Nov. we had to put to sleep another cat that we had for 6 years.  In Feb. we got a 5 month old kitten, which he tolerates.  Within the last month or so she has been going outside a well, although she still uses the litter box.  The litter box has a cover, but I think it is too tight of a space for him.  We are putting the house up for sale within the next few weeks and will be getting new carpet in much of the house.  I don't want to come home to "deposits" on the new carpet. I would also like to keep the litter box covered to show the house. He seems to eat normally.  Could this behavior be attributed to age?  

Answer
Karen,

sounds like you need to take your cat to the vet for a full exam and bloodwork, bring a stool sample too. .  Your cat could have the start of being hyperthyroid or other. Those can cause behavior changes.

Also you are making essentially an outdoor cat that has been going outdoors learn to use potty in house a bit too quickly.

You need 1 litterbox per cat PLUS one extra- that is the rule of thumbs for cats PERIOD.  Also ask your vet for Cat Attract or use the Cat Attract litter.  FYI- most cats don't like covered boxes-that was done by the pet industry for people. A shade in front of the box may make the area more pleasing.

STRESS is a huge contributor to cat problems. MY advice would be to find a cat only vet through the AAFP (american feline practitioners association) to get to the bottom of your problem then get a run around.

Good Luck