What to do when my nearly 4 month old kitten only sometimes uses the litter box?

Question

So a little under a month ago I bought 2 kittens. Rambo & Simba, they're brothers. Rambo has no problem using the litter box(es) (I have 3) and he's what you'd expect from a kitten: playful, cuddly and super energetic.

While Simba is also all 3 of those, he has some troubles using the litter box. I have 2 litter boxes in the bathroom each placed in different spots, and I've moved each from place to place in the bathroom. Rambo has no issue with this and continues to use them no matter where I put them, but Simba, however, only -sometimes- does his duty in the litter box.

I can not count the times he's done his business in the corner of the shower or on the hard floor on the balcony. He seems to do it in "hidden"ish spots. The strange part however is that he has used the litter boxes many times before, so it's not like he doesn't know where they are or how to use them. Granted he doesn't cover up his poop or pee, but I don't mind that too much as long as he'd continue using the boxes.

Whenever I've caught him getting ready to go poo in the corner or on the floor, I've gently picked him up and put him in the box and even dug at the sand with my own hands in an attempt to demonstrate how to dig a hole and encourage the use of it.

Of course he then does his duty in the box after I've put him in there, and I praise him for it, but I can almost certainly expect him not to do it afterwards, as he resorts to doing his doodoo's on the balcony floor or in the corner of the shower.

I've put food bowls on the balcony and shower floor with some food in them, of course, but he just decided to poop beside them.

Now for a strange part: he only poops a little in the box and poops the rest outside of the box.

His brother is not antagonizing him or anything, and I've made sure to let Simba do his business in peace whenever I catch him actually going to the litter box himself.

It's not a matter of cleanliness, as I clean all boxes 3 times a day and the litter is supposedly meant for kittens. It's the "Ever Clean" brand. The previous owner used wood pellets but Simba would still not use it frequently as I noticed when I went to pick the kittens up; Simba went and did his doodoo's in the corner of their apartment in front of everybody.

I simply assumed that the small kitten was stressed that so many strangers suddenly barged into his home and he just got so riled up and didn't have any time to hold back his urge.

Well here I am now with a kitten who doesn't take the hint.

It saddens me because I can't keep living with a kitten that poops everywhere except where he is meant to, because my own apartment starts smelling absolutely horrible.

He's currently on antibiotics and 2 other "medicines" that should help in case there's something wrong with his bowels which discourages him from using the box frequently, but I've seen no change in his behaviour so far. He's been on the meds for about a week.

Sorry for the long post. Hopefully you can endure through it and give me some well needed advice here.

Answer 1

Since your cat has never consistently used the litterbox, it sounds to me like it needs proper litterbox training. Some cats will take to the litterbox naturally without any or very little formal training. Others need the help to figure out out.

Besides the training, you should also do the following things:

1. Make the box as appealing as possible. Make sure it's as clean at all times as you can get it, and the box should be a simple pan without a cover, as big as you can fit. You can try other boxes once the cat is trained, but you want the cat to think this is the best spot. Figure out a location that is reasonably quiet and litter that they like and stick to it. The more boxes you have, the better.
2. In your case you mention you've already gone to the vet, but for the general case, make sure there's no underlying medical issues by taking the animal to the vet.
3. Clean your home thoroughly with cleaners designed to break up smells. Cat urine in particular is difficult to fully remove. If you get a blacklight, you may find spots that need cleaning that look clean under normal light.

Then, as to the training, I suggest using a commonly recommended technique some call "confinement" training.

1. Pick a small room, like a bathroom, to keep your cat in during the training. Put everything the cat needs in this room, including the litterbox. Make sure the cat is comfortable in there, and that you give it enough attention while it is in this room. The idea being cats generally don't like eliminating in spots they're using for other things, so hopefully the litterbox will become the best spot to eliminate.
2. Once the cat has been using the box to eliminate consistently for about a week, you can let it out into a little bit larger area of the home while supervised. If you see the cat looking like it's about to eliminate, try to distract it from doing so, and then put it back in its room with the box. Also return it to its room when you cannot supervise it.
3. If you have success, you can gradually grow the area its allowed in and reduce the amount of supervision until you're convinced the cat is fully trained.

Answer 2

You might try to put the litterbox at the spot your cat uses most often. Take the top of from your litterbox to make the kitten feel more safe.

Do not move the litterbox from place to place in your house. Wait until your cat is comfortable using the litterbox before you move it.

You might want to change the type of kitty litter you use to see if this might help. Maybe put different litter in each box and use the same type of litter for a couple of weeks.

Using medication for an unknown illness is probably not the best thing to do. Antibiotics will often cause diarrhea, so I do not think this is good idea.