Just had a recent bout of coming home from a vacation (during which we had unusually cold nighttime temperatures) and discovering one of our older Buckeye hens with what I figured was likely gapeworm. I wanted to post this experience because I gained the answer to the one thing I couldn't find anywhere when I searched: How long after treatment with wormer can one expect that the bird will be recovered? The answer is, 24-48 hours for 90%+ improvement. This was a fairly severe presentation, with the hen likely having lost 80% of her airway...I was going to give her a day and then euthanize her if my diagnosis was incorrect. She was not only gasping for air but she was making a strange and incessant sound like a bark or cough...not unlike the first note of a rooster's crow, accompanied by a shake of the head. The more I read about gapeworm the more I realized she was likely trying to clear her windpipe. I was unable to visualize the gapeworms when I looked down her trachea with a flashlight. All I had on hand was a packet of equine Safeguard (22.2% concentration) that had expired in 2005....the bird didn't have the luxury of waiting for me to get to the feed store tomorrow. I found a treatment formula online that used 10% liquid Panacur. I had granules,and was treating one bird not an entire flock. So I did the following conversion; 0.43 gram of the 22.2% granules dissolved in 10 ml of water, and mixed into one-half pound of feed was what I offered first. But then I read that a bird this sick is so busy trying to breathe that she might not eat. So I mixed up another dosage of 1.5g in 10 ml of water and gave her 2.5 ml of this orally via syringe, trying to use close to a dosage of 5mg/lb of body weight. I had read that when chickens were experimentally overdosed with Panacur, that no fatal effects were seen even at 1000 the therapeutic dosage, so I felt as though I had some leeway to err should my little electric balance be off a tiny bit. I also left her the medicated feed...I figured if I had 1000x as my leeway, making sure she was really dosed well (does the efficacy of the fenbendazole decline over time? One never knows how arbitrary expiration dates really are) was a priority. Within 12 hours of the dosage she was breathing much better. Within 24 hours the coughing had reduced by about 60%. It is now approaching 48 hours and the respiratory noises are down to maybe 5% of when we found her. I'm guessing that after the worms were dead they had to be coughed up? I'm unsure how fast a dead parasite disintegrates or how exactly the trachea clears.....blech. Although I think her becoming infected was an isolated incident, I will likely repeat the oral dosage in 2-3 weeks just to be sure. If she remains improved at her present rate, I will release her back to the flock tomorrow. Anyway I hope this will be of some help for the next person who is dealing with this.