Okay, what sort of footing does she have on the bottom of that swimming pool.....I know NOW I'm asking....could she have gotten up to stretch and kinda slid a bit? I know you've got the chips, but now I'm asking myself.....mmmm,,,,I know that plastic can be slippery.
I wonder if she needs more stable footing on this setup....
Don't go and do a thing until others say something here......
I sure wouldn't move her set up at this point in the brooding........If it were me, What I might consider is gently moving her chips and putting down a layer of sand she could stand on our even potting soil,,,and then the chips on top of that,something firm for her if she decides to walk out of the box when you don't see her. I know you haven't seen her get up, but it's possible she did when you're weren't there unless she's on camera...smile.
Now, please wait Cheryll to see what others are saying.....