Hi All, we currently have 2 ferrets we bought together as kits 1 year ago.  My wife and I have owned another ferret in the past before these two so we leveraged that knowledge in training them but we're still having issues. I apologize for the length of this post ahead of time :)

Both ferrets live in a Ferret Nation 181 cage with the single level. The food and water is on the upper platform.  I got 2 high back littler boxes and cut them and then bolted the 2 sections together to make a litter box that spans the entire width of the cage under the platform.  It's large enough so both ferrets can fit inside it at the same time so space is not an issue.  Both of them had issues going potty outside the box as kits, but for the most part, they grew out of that.  Except one of them.  He's a dark sable, and every other day he will go potty outside the box, but he still also goes inside the box.  It can be very random, sometimes he will do it when the litter barely as has anything in it and sometimes when it's got a lot.  Likewise, he will use the litter box randomly, sometimes when it's pretty clean, sometimes when it's not. I've tried emptying the litter even twice a day but it doesn't change his behavior.

I notice our dark-eyed white ferret pretty much climbs in the litter box and then meanders around for a few seconds and then goes potty like clockwork. He just climbs right in, he's picky in where he actually goes but never picky about getting in the box.  Our dark sable seems to smell the box first, and act very finicky and put one foot in and then back out.  Sometimes he gets back in the box and goes, but I can tell he seems to be very picky.  I know he knows the proper thing to do is go in the box, and when I witness that I always reward him with words and a treat.  But it seems if he doesn't like the first smell or touch of it, he backs out and goes right next to it. Once in a while he will go potty on the upper platform where his food and water is. Keep in mind that nobody is usually around when he goes outside the box.  If I am there watching him and he backs up, I immediately open the cage and place him in the box.  I rarely catch him in the act so there's no good way for me to discipline him for it.

We have not put anything on the bottom floor so it's just the bare plastic, it makes it much easier to clean.  I tried putting down bedding like my previous ferret had, but our dark sable goes potty in the same spot, right on top of the bedding.  I've moved things around and tried different arrangements.  I've found that if he can find a bare spot on the floor, he will go there, even if he might have to step in it or near it.  I'm pretty convinced that unless he gets over his issue with being so picky about the box, he will just find a spot somewhere else to go.

I've tried many things and I'm running out of ideas. He's been full grown for a while so any of his kit tendencies should have gone away. I've thought about putting old t-shirts down but he's a chewer so I think he'd probably just tear them up and eat some of the fabric.  Any help with this issue would be greatly appreciated. 

Thanks,
Dan