My hen had something that looked similar. Initially, I thought it was wet pox, but since there were no mosquitoes to transmit the virus, I treated it as if it was canker with a secondary infection. She was showing similar symptoms to the ones you described, but she was also itching at her throat a lot and had trouble eating and drinking. As soon as I noticed her symptoms, I isolated her from the flock.
HERE WAS MY TREATMENT PROCESS:
- I treated her with Oxytetracyline for a week (I purchased this from my local farm store). I put this in her water once a day
- I gave her vitamins and electrolytes in her water
- I also treated her with Fish Zole for six days (I had to purchase this on line). I dissolved one pill in a tiny bit of water and mixed a little food in with it to create a mash. I gave this to her once a day.
*I also gave her meal worms sprinkled in her water once a day to encourage her to drink and to give her extra protein
My hen is now laying eggs and doing great!! Luckily, none of my flock is showing symptoms.
Good luck with your hen