Yellow stuff growing in corner of beak...

[Ederle]

I have a four y/o polish hen, Margot, who I noticed had a slightly swollen face one day. I thought she'd been stung by a bee or something, but then I looked inside her mouth and at the very corner of it was a bit of pale yellow stuff, about the consistency of jello.

How do I get rid of this? I've been putting an antibacterial spray (one which is safe for her to accidentally swallow) on it and scraping off the yellow stuff, but it grows back within hours.
Margot's acting fine, and her face isn't visibly swollen anymore since I've been cleaning it everyday.

How do I treat this?

I should also mention that I have two hens that have had a similar yellow-ish substance growing on them, but it's been on their vents. One seems to have gotten over hers, it hasn't been growing back and she's finally laying eggs again. The other has improved, but the yellow stuff is still there.
Probably unrelated, but I also currently have two cases of impacted crop and two other hens with internal laying

 

[azygous]

There's a particular respiratory disease called canker. It can spread all the way down the digestive tract in addition to affecting the mouth and throat.

If you can call around and find copper sulfate, that's one way to treat canker. You offer it as the only water source for four days.

• 2 ½ liters of water
• 1 teaspoon of apple cider vinegar
• 1 gram of copper sulfate
  
  Another treatment is Metronidazole https://www.revivalanimal.com/product/fish-zole?sku=22166-698 250mg for each chicken affected daily for five days.

 

[Ederle]

There's a particular respiratory disease called canker. It can spread all the way down the digestive tract in addition to affecting the mouth and throat.

If you can call around and find copper sulfate, that's one way to treat canker. You offer it as the only water source for four days.

• 2 ½ liters of water
• 1 teaspoon of apple cider vinegar
• 1 gram of copper sulfate
  
  Another treatment is Metronidazole https://www.revivalanimal.com/product/fish-zole?sku=22166-698 250mg for each chicken affected daily for five days.

@azygous
@Eggcessive

I have a rooster who is breathing a bit noisily now, and his crows seem a bit more gurgly than usual. Should I treat him as well?

 

[azygous]

If you use the copper sulfate treatment, it's wise to go ahead and treat the entire flock.

 

[Ederle]

If you use the copper sulfate treatment, it's wise to go ahead and treat the entire flock.

What about the fish zole? Could I use that on a chicken that may not be infected?

 

[azygous]

Yes. Canker is extremely contagious, so treating all the flock is warranted.