I have my 3 silkies in a box in my bedroom as they all have seem to be inflicted with the same systems. I am feeding them Lafeber's Nutristart baby bird formula with a syringe. The "gaping" had stopped with oral treatment of Ivomec injectable given orally. I am giving Poly Vi Sol and crushing a selenium tablet to add to the vitamin E capsule daily I dusted them with 5% sevin dust and I change their bedding daily. Two were getting better but I goofed and added the third Silkie as they all seemed to start all over with gaping, violent head shaking and lethargy, so bringing in the 3rd one it seems to have started the cycle all over again in all 3. Shame on me, but it's not easy to have 3 seperate chickens in my small bedroom and I have no way to line my bedroom with cages so I have them in a box together. I have 2 eating on their own sometimes, but still syringe feed them and give them vitamins. One has become truly accustomed to being hand fed and enjoys our time together. Another seems grateful and sits on my lap anxious for the syringe full of food. The new addition fights with me some to get the meds in her but is the strongest of the 3. They are all 3 now showing overall improvement, but declined rapidly when I put them back in the chicken run with the rest of the flock, so they will live separately for the remainder of the winter. I have a rabbit cage that I am changing them over to and am gonna wait out the winter before I add them back to the flock. The run is wet and muddy with all the rain and snow and they HATE it. Spoiled chickens, but safe and happy in my dry warm bedroom. Lol.
I researched for a product to kill gapeworm and found Ivermectin to be not only suggested but supported as a treatment for them on several sources. There are lots of varying opinions about most medications for all illnesses in chickens, it's hard to sort out. I can report success with 2 of the silkies and with patience, treatment, vitamin e, syringe feeding Nutristart Baby Bird Formula and a lot of love they have returned to the chicken coop. I'm struggling with one of the hens with a really bad bout of diarrhea that I can't seem to get under control. The other hen and rooster never had diarrhea so I'm unsure what is causing it, but I'm continuing her stay in the box and hopefully can figure it out. It would seem simple to fix, but it isn't with her.
I did quarantine all the new birds each time I bought new ones. I didn't mean to imply that I brought a bunch of chickens home and put them all together immediately. The silkies I actually bought from Tractor Supply when they were 2 weeks old this past spring.