help with potty training

Question
My 9 month old pig is starting to be a booger about going potty.  He used to be fantastic and go in his litter box whenever I walked him to it. Within the last month or so, when I walk him down to see if her needs to go potty he acts like he doesn't need to go and 2 minutes later will sneak over into a corner or somewhere hidden and do his business.  The odd thing is.. it's not always the same spot so I don't think he's picking up a potty scent anywhere.

Also, for about 6 months he was confined to a 3x3 pen.  just big enough for a bed, litter box, and food.  When he started using his litter box really well we opened the pen up to about a.. 6x6 area.  which he seemed to love and still do well with the litter box.  Until recently he started pooping and peeing in the corner of his pen.  The litter is clean and fresh.  I always keep one or two poops in there to remind him that's where to go.  He's an indoor pig and neutered as well.  Can you give me advice?

Answer
It's possible that piggy was having small, unnoticed pee accidents for a while. When the accidents were not caught, he just assumed it was Ok. Now that he's bigger the accidents can not go unnoticed.

Piggies like to have a bit of room when they potty. They also hate to have to step up or over something to go potty. It's possible he's outgrown his litter box and needs more room.

Can you move a larger box to the spot in his pen where he is pottying? Pigs usually do not like to potty near their bed or food, he may be trying to tell you his box is too close to his bed.

He needs to go back to basic potty training. Take him to his box when he wakes up, after eating, etc. Do not let him leave his box until he potties. Right now he's used to pretending he does not need to go, then sneaking away to potty. So you know he needs to potty. Do not let him have a choice of where to potty, it must be in the box and he does not leave the box until he potties. He might not be very happy the first couple of times, but he will catch on.

Also, clean all the accident spots with a cleaner designed to remove pet urine odors. People may not be able to smell it, but he will and it will remind him.