You can check her pelvic bones easily. Hold her so you can see her vent. You will be able to feel her pelvic bones by pressing your hand just below her vent. There will be two knobby bones sticking out, the amount of space in between the bones will tell you if she is laying or not. If you can only fit 2 fingers in between them, she's not laying. If you can fit three or more fingers between, she's either laying or going to shortly.
Ok thanks! I'll be sure and check her tomorrow.