I'm not an expert, but it appears to me that they were cannibalized by the other chickens. I would take a good look to see if they have enough room, and can be let out during the day to range. Also look at the protein level--16% is pretty average for layers, and you can bump it up to 20% either by giving some higher protein gamebird feed (24-26%) or switching to all flock raiser and supplementing calcium by adding crushed oyster shell on the side. Do you notice any overly aggressive hens? The 3 hens need to be separated to heal. Clean them with hibiclens or betadine weakened with water, or plain dish soap and water. Neosporin or Bacitracin ointment should be applied for a few days until it tarts to heal. Then I would use BluKote, Bag Balm, or an anti-pick lotion. Occasionally there can be a vent prolapse that may cause this picking, but with 3 affected, it is probably from lack of room.
