Eprinex is a POUR ON... (directly onto skin) -- not given orally.... and is a wormer that does not kill tapeworms, but does kill mites and lice.
Valbazen is the best all around wormer, kills every kind of worm.... but, does not kill mites. Seven dust, or "poultry dust" for mites (if you use Valbazen to worm). Both (each) would need to be repeated in 10 days, WITHDRAWAL PERIOD for Valbazen. Use search here on BYC for worming, how much valbazen to give, and use more recent postings for best info. Clean coop, roosts, etc... sprinkle some Seven Dust or Poultry Dust into the nesting boxes, over any dirt they "bathe" in, etc. Repeat in ten days.
I am assuming you know that giving the wrong kind or too much of anything can kill your chickens. And, it is always best to catch and dose EACH bird, to make sure that each one is getting the correct and accurate amount of medicine. Some antibiotics, like the Duramycin-10 (which is Tetracycline) is available at any feed store, and can be added to the drinking water for the entire flock, 1 tsp. per gallon. If antibiotics have already failed, then it is not a problem that is treatable with antibiotics, I would assume.
I suggest that since you are spending money on meds and have a large frustration level from all this -- the state vet, or any veterinarian that will examine and treat a chicken/birds would be your best, the thing to do.
It seemed my chickens kept getting sick... (repeatedly) -- I would treat them with antibiotics, and they would get sick again a week after stopping the antibiotics. I was tired of the sick birds, the withholding of eggs, all that... it was very frustrating.... until I found the right information on worming the correct way with the correct wormer.... I got them wormed and within 24 to 48 hours -- it was amazing... the dramatic difference in the chickens, the behavior, running, playing, mating more, laying more... and the one that was limping, stopped limping. The ones that were "droopy" perked up.
I was able to buy Valbazen from the feed store, from an open container he had.... so that I didn't have to buy a huge bottle for my smaller flock. I dosed them with the Valbazen 1/4 CC/ML per bantam... 1/2cc/ml per Standard size chicken.. each one, ORALLY... careful not to put it in their windpipe... had to have a neighbor catch each one, one at a time, he held them, I dosed them. Repeated it in ten days... Withholding eggs (or culling) from the first dose.. to the 15th day after the second dose.
I know... that seems a long time. Clearly, you would need help to do this worming. And, while it might be right and suggested to wait to do this for ANY OTHER med to get out of their system.. you might need to go ahead and worm, if you have not wormed EFFECTIVELY yet. If you have wormed with anything, you need to wait ten days before worming again. Worms can kill a chicken, all your chickens, and the symptoms are varied from my experience. And, I never saw a worm in their poop either.
Look for recent posts on worming from dawg53. Look at all the information..... use the search and you can rely on information on worming provided by dawg53, he gives dosage and types of wormer info. We all learn as we go and experience, so recent posts are better for up-to-date info than older posts.
I am no experienced expert, do not take my word... I am just trying to give some information from my experience. I hope some part of it helps, or gets you to the right information.
Good luck.
