If you're going to use the zimectrin gold for your Leghorns, dosage would be a
"small pea" size amount given orally to each hen. Then redose them again in 10 days.
Yep, those are tapeworm segments. You dont need a vet to tell you those are tapeworm segments. Either get what Michael Apple suggested or get Valbazen or Zimectrin Gold and dose your birds.