I only have two Rhode Island Red hens and they are three years old. One is showing signs of worms by laying only soft shell eggs that break open even before she lays it. I have searched the net for both natural remedies and drugs. The gentlest drug, Piperazine, and it only covers round worms, does say on the label NOT for egg layers. I have been using some diatomaceous earth mixed in crumbles but obviously not enough. I just started putting 1 tablespoon apple cider vinegar in I gallon of water. I realize these natural things are probably only going to control the worm population and not really get rid of them. So it looks like the odds are slim my hen will ever be healthy again and could likely infect my healthy hen or already has. Any suggestions from more experienced chicken keepers would be most welcome. Thanks!