new kitten issue

I just got a new kitten, about 12 weeks old, and I kept her closed in my spare bedroom with a litter box and food for the first couple of days because I have a second older cat. On the 3rd day I let her roam the rest of the house including the downstairs. Everything was fine until after a few hours she went to the bathroom in the corner of the living room. Do young kittens forget where their litter box is if you have a big place ? It wasn't an issue with my first cat because I only had a 1 bedroom apartment then. Since then I just take her upstairs every hour or so to make sure she is near the box when she needs to go. If she is forgetting, how long til she remembers where everything is ?

Not necessarily that the kitten forgets; its more that the kitten cannot get to the pan fast enough. Thats why its good to either confine them in one area for longer or put a few small pans around the house and over the next few months, eliminate them one by one.

I would say by the time the kitten is 4-6 months old they know where the pan really is and are capable of getting there in time.

Maybe she didn't want to use the one the older cat's used to (but couldn't reach her own or forgot it).