She may be egg bound or internally injured. Get her into a lukewarm tub deep enough to float in for about an hour or so, prepare some kind of treat with extra calcium in it - sardines packed in water with no salt, powdered egg shells, or if you can send someone for some calcium gluconate 23% solution (feed store may have it, vet may have it) and give her a half a teaspoon of that.
Keep her quiet and safe with fresh water and food.
A vet is the best help - if she keeps straining she could prolapse. If that happens, a vet who can deal with that (extract egg, a couple of stitches in the vent) really would be worth the trip.