N.J.
Has she had problems with constipation? Is her poop soft? I know, TMI but that could have an effect. I was having the same problem with a little guy in my daycare. I started giving him a glass of prune juice mixed with apple juice everyday to help regulate and loosen his stools and within days he was pooping on the potty. I was talking to another childcare provider last night and she gives the kids temporary tattoos when they use the potty. The kids love it because you can't loose it like a sticker.
~N.