I used to use ivermectin and eprinex long ago and found both ineffective in treating large roundworms. Some types of poultry mites are showing resistance to ivermectin as well. I suspect resistance due to overuse as a miteacide in poultry.Nope. Not cost effective nor timely enough for my needs. I own the machinery that created the bird im trying to save. It's cheaper to make another one or perhaps a better one from that machine or save it with coventional or unconventional meds. I have absolutely no emotional attachment to any of my stock. If i keep my breeding stock for more than 2 seasons I'm either stagnant or moving into the past.
I worm with ivermectin every 90 days. Cheapest feed i can buy. I have yet to have any signs of internal parasite load. I vary the concentration by the time of the season. Summer dosage level when the are drinking gallons/day is ineffective winter dosage when they are drinking gallons per week. I'm always willing to learn so if you have research based info substantiating that ivermectim doesnt work it would probably benefit the entire forum by posting it and making it a sticky.
When handling a 12lb heritage cornish rooster it easier to give them an injection then restrain and open their mouth with one hand and dispense an oral solution and avoiding having liquid aspirated.
I switched to benzimidazoles and pyrantel pamoate and havnt looked back since.