That is good, so if you can get the bleeding stopped and to clot, she may be okay. Do you have any idea what attacked her? Are you other chickens safely locked up?
Can you try to get the bleeding stopped by holding some pressure? Corn starch or flour is good to help clot a wound. Her crop looks very large in the picture, and watch for any fluids to leak out of the wound. I would keep her inside in a dog crate to watch her closely. Provide food and water...
Have you checked to see if her crop is punctured or ripped open? Vetericyn, weak betadine, hibiclens or chlorhexide with water, or plain saline is good for wound care. Initially, a kitchen fawcett sprayer can be used to flush or clean out a dirty wound. You may want to pull any feathers over her...
Normally I do not recommend doing crop surgery at home. I would see a vet if possible, but if her crop is open and leaking, then she won’t be able to eat and drink. Do you have Poultry NutriDrench to give her a few drops orally? Here are some videos on crop surgery one with super glue to close...
Vetericyn or a similar wound spray is good to use after the bleeding has stopped. Take some paper towel or gauze and put pressure on the wound for several minutes to see if it stops. Offer some water from a cup. Look at the wound to see if the crop is visible or if it is ripped open. That is...
Sorry about your hen. It appears that her crop or chest was wounded. Can you look her over to see if her crop is open? That is where the food and water are stored after eating? What do you have at home for disinfecting a wound? Look for any hidden cuts or puncture wounds. How is she acting? If...