You are a caring pet owner & doing, learning , all you can, bless you. Time, treatments, & lots of patience will tell about the healing length. We can only let Nature do its own timetable of healing. I've kept many healing birds indoors in crate for days, sometimes weeks. It's the choice we made when we have pets.
Hurt? I dont know the pain tolerance of hens but I cant be scared if I have to treat a bird. I was at first squeamish but know now I have to do what is necessary to treat a hen. The bird will feel your confidence too.
We've had over the years bumblefoot, dry pox, Mareks, heatstroke deaths, avian leukosis, ovarian cancer tumor, had to learn tube & syringe feeding, and a bird who scratched so hard she tore off toenails & actually lost parts of toes so we're no strangers to treating sick/injured birds. But we learned & we grew more confidence over the years & it made us appreciate God's creations & how they have the ability to heal. Not all our efforts have saved birds but most survived our treatments and we've lost none to bumblefoot yet