It looks like it could be an ingrown feather, but mine was not hard like bone. BUT...that doesnt mean yours isnt a feather either. But it does look like it needs attention, especially before it infects.
I would gather so supplies like alcohol, corn starch or some sort of blood stop, (mine did not bleed, but if yours is infected it might) tweezers, dental picks, scissors, even a scalpel...any instrument you use should be boiled in water for 5 mins and soaked in alcohol for a couple of mins after boiling. You dont want to cause infection.
I would either towel her up if possible or have someone hold her. Poor some alcohol on the area and then start working on it. Pick open the tip and see what is in there. If you hit feather right away, gentely pull it out until it unwinds. It will be curly. There may be several of them in there. If you hit blood or pus, you may need to squeeze it all out like a zit. Only use the tools if you have to go deep. Use your judgement. But like bumblefoot, if there is infection, make sure to get as much as possible out of it.
Once you are done, give it another douse of alcohol or even a one time only douse of hrdrogen peroxide. Then I would apply some sort of antibiotic lotion. I dont care for BluKote, but if it is all you have, use it. Moist is usually better for deep wounds at first, hence the ointment type lotion. Then, if you have a hen saddle, I would keep it on her over the wound for a week or so. Even a scarf tied on around her. Dont let any roosters mess with her until it is healed. Same with other hens. Check it daily for infection and keep applying the antibiotic ointment for a week or so, or until the skin has hardened over.
Please keep us posted on how the surgery goes!! :-)