I don't know about coxoid, or Lanacane.
Rooster Booster vitamins are fine, but I don't think it's necessary.
Do you have any Vaseline? You can use that to keep the wound moist to heal properly.
She may have a sprain, or pulled muscle.
Normal feed is fine, you can spoil her alittle with...
How far does it extend on the back?
With the blukote it makes it hard to see what all is going on. Too me, it looks like a large flesh wound which would heal up fine with regular cleanings, & applications of non pain relief triple antibiotic ointment.