I really an no medical expert. Identification is my area of expertise.
I can try to help a bit, though.
Any visible bleeding, wounds, broken legs or other abnormalities? Is she holding her body weird?
Does she seem to be in pain when trying to stand, or does it look like she's almost too dizzy to do so?
Is she laying?
If so, when did she last lay?
If it happened very suddenly, overnight, and she wasn't in proximity to anything toxic, it's possible she may have Obturator Paralysis. Where, an egg, most often of an enlarged size presses up against the obturator nerve which can cause paralysis of the legs. It tends to resolve itself, but if you're at your vet, and that is the case, administration of oxytocin and fluids may be recommended.
Trauma or ingestion of something toxic prior in the day are both possibilities.