OH...and make sure that water bowls are placed AWAY from food bowls. Cats instinctively know that if a food source is too close to water, the water may be contaminated. They don't quite make the "but it's in a bowl" leap.
THANK GOODNESS, and thank you for letting me know! I'm going to sleep much better tonight.Mamanyt1953 She pooped about an hour ago, thankfully. I'm pretty sure it's the Purina that constipated her, because she was irregular when I was feeding her that exclusively.