I'd start Corid 9.6% with the outside hens at 10 ml/cc, or the Corid 20% powder at 2 tsp per gallon of water for 5-7 days. The problem with something like this is it could be worms, but you treated for worms. It could then be Histomoniasis (Blackhead), which is a protozoa infection carried by caecal worms, Coccidiosis, or bacterial enteritis. We don't know for sure unless you could have fecal examination by a local avian veterinarian. If you absolutely cannot find a vet in your local area, treat for Coccidiosis. If in three to five days you don't see improvement in droppings, you may want to treat for E.Coli infection. There is no withdrawal time for Amprolium, and you should not dose water while feeding medicated feed. I stopped using medicated feed a number of years ago since it didn't prevent birds from getting Coccidiosis.
Your rooster is still sneezing and you only have one more day with tetracycline in water. After that last day of Duramycin in water. Supplement water for the next three days with vitamins-probiotics in water for him. Keep a watch on him. Take him outside when you can so he doesn't become intolerant of the cold. You may have trouble re-introducing him to the flock with that other cockerel/rooster.
Your rooster is still sneezing and you only have one more day with tetracycline in water. After that last day of Duramycin in water. Supplement water for the next three days with vitamins-probiotics in water for him. Keep a watch on him. Take him outside when you can so he doesn't become intolerant of the cold. You may have trouble re-introducing him to the flock with that other cockerel/rooster.