Small and crowded is good. Though I suppose smaller hides would fit her better.

I was unsure to answer about how you just watched out of the corner of your eye. The two opinions above are both very valid for the reasons they state, but I think that I would prefer to be on the cautious side. I think I once heard of rat running right up and chomping down on the snakes neck, severing it's spinal cord and killing it. Obviously an exceptional case, but I wouldn't trust them alone with my snake.