Hi!
I am nowhere close to being an expert, but i can guide you a little and hopefully someone else will chime in. I know how frustrating it is to post an emergency and not get an answer. Does your chicken have any signs of a respiratory illness? Do you see any small bubbles in her eyes? is her face swollen? hold her chest to your ear....do you hear any crackling? You may have to wait until she is going to sleep to be able to notice these symptoms. Also, have you seen any sneezing? These are often indications of respiratory issues in chickens...my understanding is that sometimes they can builld immunity and fight them off, and sometimes they need an antibiotic. Either way, they will always be carriers for whatever the issue is, even if they fight it off. Some people choose to cull any bird that has a respiratory issue. Because my flock is a pet one, and i am not selling eggs/breeding or showing, i would personally prefer to try and help them fight it off.
As for cleaning the nostril. There is a product that is called VetRX that i have used with much success when one of my girls had a respiratory issue. It is a natural blend of oils, much like Vicks Vapor Rub for people. You can buy it at pet stores and at feed stores sometimes. They make one just for poultry, but any VetRX will work. You heat the bottle in a cup of hot water until the oil is warm, and then mix a fewdrops of warm oil with a little of the warm water. Let it cool until it is confortable, and, using a new q-tip for each nostril, and for each bird, swab the nostril. You can also but a few drops under their wings where they lay their heads to sleep. The vapors will help them breathe.
I saved a link for a great thread on here and I will share it with you. ThreeHorses shared her approach for treating respiratory issues, and it worked great for me.
One of my chickens was sneezing, had some nasal crusting/discharge and bubbles in her eye. I decided to try and treat my whole flock with things to boost their immune systems prior to treating with antibiotics. Every morning i gave my girls a scrambled egg (protein, and they LOVE it) with a small amount of cod liver oil (Vit A-good for respiratory issues) and probios probiotic powder mixed in (you can get this at a feed store). In their water durning the day they got 1 teaspoon of organic apple cider vinegar per gallon of water (Must be non-pasturized, you need the bacteria in it). At night, I would warm the VetRX and use it under all of their wings, and wipe the affected chickens nostrils. I also would give them all 2 drops of poly-vi-sol baby vitamins WITHOUT IRON dribbled along their beaks before bed, they hate the taste of the stuff, so you really have to hold them. I drizzle it along the beak so they get it when they open their beak, i am too scared to try and drop it down their throats because they can aspirate.
My plan was to try this for a week, and then do antibiotics on the sick one if they did not get better. Within three days i saw a huge difference in the sick bird, and after a week i weaned them slowley from all of the vitamins/supplements. Now, i give them the egg/cod liver oil/probios concoction once of twice a week just as a boost.
As for antibiotics, i had purchased duramycin-10 to mix in their water if the whole flock needed it, and Tylan-50 injectable and ,22 gauge needles if i only needed to treat the sick one. I actually never used any of these items, as i prefer not to use antibiotics if i don't have to. So far, so good!
Even if it is not a respiratory issue, this treatment will boost their immune systems all around, and could not hurt. If the birds were deserted, they may have been malnourished as well. I would make sure they have a very high quality feed and wholesome treats like the scrambled egg and a little yogurt.
I hope this helps and i wish you luck! It was very good of you to rescue your neighbors birds!
Here is the link where i got my information. Very, very good advice!
https://www.backyardchickens.com/forum/viewtopic.php?pid=2788452
Andrea