2 of the Trio of Nuts (almost 6 weeks old) seem to not want to urinate when I stimulate them much (just a few drops or so). They have always done well, until now. BUT, when I put them in the potty box after I have stimulated them, they almost immediately squat down and urinate all over the paper towels. They still always poop when I stimulate them, though. And there is poop in the bedding, but only at the very bottom layer of blankets. SOOOOO.....do I continue to stimulate them for a while, since they may not be completely emptying? How do I know that they are ready to graduate from that part of their childhood?