I sounds as if your saying the feathers were pulled out, no damage to the skin and you can see the base of the feather still in there? Sounds like you dont have too big of a problem at all. Chickens lose feathers all the time. Think of the base of the feather as a straw. If you take the feather out and leave the 'straw' in there, blood will come out until it dries over and in some cases, the blood will not dry and your bird can bleed out and die, however, that is not your case.
Your bird will not grow these feathers back until it molts. Unless you pull out the little base peice left in the skin. Use pliers, grab near the skin and give a quick pull. It should not bleed at all but in the case it does, use quik-stop powder or some flour. I pull broken feathers all the time on my birds. They will grow back fairly quickly.
Others may pick at it, although I have not had problems with that, just keep a good eye on them for a little bit. I see no reason to treat with any antibiotics as it is only the feather being pulled out.
Everything I just wrote is if there is NO WOUND!! which it sounds as if there isnt. If you would like, you could post a pic. Best of luck to you.