Yes, it sounds like the beginning of a respiratory problem. The first thing that I would do would be to isolate both birds in a clean, warm environment. I would give them some vitamins and electrolytes in their water, and make sure that they are eating and drinking. If they seem a bit uninterested in food, try giving them some scrambled eggs, applesauce, or normal layer feed that has been moistened. Any other treats that they like would be good, as well.
I would try just giving them the care described above for two days. If you see no improvement, I would start them on Terramycin (also known as Oxytetracycline), which is an antibiotic that treats most respiratory diseases. You should be able to find Terramycin at a livestock supply or feed store, or possibly order it online. The dosage is 1/8 teaspoon per cup of water for 7-14 days. Mix a new mixture up daily, and do not give probiotics during treatment. You might want to treat your entire flock with Terramycin, as respiratory diseases spread easily.
If Terramycin doesn't work, you can try giving Tylan injections. Tylan is one of the strongest antibiotics, and when one of my chickens was sick, it was the only antibiotic that worked. However, I would only give Tylan is other antibiotics have failed, as it can be hard on a bird's system.
The best way to give Tylan is through injections into the breast muscle. Dosage for a large-fowl chicken is .5ccs once a day, and for bantams it is .2ccs once a day. Alternate the side of the breast you inject in, as Tylan can make the injection area painful. You can find information on how to give injections by doing a searching the Internet, or looking on BYC.
Good luck!