Offer her some water with sugar 1 tsp per cup or electrolytes to treat for shock. Keep her warm and in a quiet spot separated from others. Look for any hidden wounds under wings or under her feathers. Dogs tend to chase and play with chickens and may grab and squeeze them, which can cause internal injuries. Time will tell if she is okay. If you find any wounds, just use some saline or chlorhexidene to clean them, and apply some plainTriple antibiotic ointment twice a day. Let us know if she is able to stand. I would keep her inside in a wire dog crate and offer water and food often.
I lost one out 3 hens who jumped a chainlink fence from their chicken yard into my backyard where my golden retriever was. The first 2 survived, but the last one with no marks or missing feathers died within 15 minutes. Another escaped the yard and a neighbor’s dog who was with it chased the hen all over removing feathers, and causing scrapes. She survived, but was sore for a few days. She was our best layer, but afterward, her eggs were all soft shelled. The attack through her into a sudden molt as well.
We had to train our dog with a shock collar, and he no longer touched or went near a chicken in the yard. Electric poultry netting solved the issue of chickens jumping up to and over the chainlink fence. I would try to make sure no other escape the run.