First, I must say that I am quite concerned about your lass’s breathing. If it is laboured, then her lack of appetite isn’t unsurprising since she likely cannot spare a breath to even eat. And while that comb is normal colored now, I am concerned about how long she can maintain that level of breathing and keep a good oxygen level for herself.
Now as I am sure you can appreciate, these signs raise a number of concerns. If she is the only one affected, then we’d have to be wary of throat obstruction, tumors, and toxic exposures. Though more often we will see these kinds of signs due to infectious processes like bacterial, viral, parasitic, and fungal issues. Specifically, we’d be concerned about such agents as acute Fowl Cholera (Pasteurella multocida), Influenza, ILT IRT, infectious bronchitis, Chlamydiosis, and mycoplasma. Furthermore, we also have to consider agents that would cause signs within the throat, like Trichomoniasis (canker), Fowl pox (wet form causes canker lesions in the throat) and Syngamus trachea (gape worm) infestations.
Now any respiratory infection of the bird must be taken seriously since respiration is critical to life. If you are comfortable handling this poorly lass (and she doesn’t get to distressed with this), then you can potentially narrow down a few of these differentials at home. If you are comfortable doing so, you may consider having a peek down her throat to rule out you gapeworms. You may be lucky and see them or one of the other causative agents (ie the plaques of Fowl Pox or discharge of canker). If you can't see anything, since you can only look down a chicken throat so far, then you can try the "Q-tip test". To do this, you need to place the bird in your lap as you have, gently open her beak, and swab a cotton bud down her throat (twirl it as you do this). Twirl as you bring it back up, and if she's got gapeworm, you'll see thin, red strings on the cotton bud. This way you will know if this is the cause. But if you end up with a cheesy discharge then canker or pox would be higher on the differential list. And if there is any other discharge, the bacterial causes would be suspect. And once you have identified what is present, you will be in a better position to know if you are treating them appropriately.
Otherwise, further measures to pinpoint the causative agent and increase your treatment success, you do want to consider involving your local vet. Especially as labored breathing is a sign of very advanced stages of disease and likely needs intensive care +/- oxygen if she is going to survive this. Therefore, it would be ideal to consider having her examined at this stage. The vet can listen to her lungs, examine her airway, and help you determine which of the above is present and thus allow you to treat this effectively. Furthermore together you can collect some respiratory secretions from this bird to be cultured. This will tell you what agents are present and what treatment will actually clear them . As well, you might consider having a fecal exam performed as well to tell you if parasites are playing a role (directly or via compromising the immune system).
Now just to note since gapeworm is a concern here, if she has never been wormed, then you could carefully do so now. That way you can directly address one terribly common differential that can cause these signs. And if you are keen and have a microscope, some poultry owners do check fecal samples themselves, and this may be an option for you to see if there is any sign of gapeworm eggs to help you determine if they are a threat here. You can find a good Fecal Sample Evaluation Guide @ http://www.rvc.ac.uk/review/Parasitology/Faeces/Purpose.htm.
Furthermore, once you have samples for culture (which will tell you what drugs any pathogenic bacteria present are vulnerable to), you can consider a broad spectrum treatment to try and tackle as many of the bacterial causes as possible. There are a range of options that would include erythromycin, oxytetracycline, or fluoroquinolones (useful if Mycoplasma is diagnosed and can be used if she isn't laying eggs), macrolides. Other options may be tilmicosin, tylosin, or spiramycin.
Otherwise, supportive care is that key facet that we need to make sure you are addressing for her. Now I am glad to hear that she is still eating/drinking, but we need to monitor and ensure it stays that way. Otherwise, we will need to initiate hand feeding to keep her hydration and nutrition intake up (since these often complicate ongoing illness and makes them even more poorly).
Just to note, if you think she is congested at all, you can try to reduce her congestion by using a bit of steam treatment here. You can achieve this by putting her in a carrier in the bathroom while you run a hot shower. Or if you have a nebulizer/humidifier you can set up a wee steam tent (by putting her into a carrier and covering it and the humidifier with a bed sheet). This can just help reduce some of those airway clogging secretions and help her to breathe easier.
Overall, there are a range of agents that can be to blame for the signs you are seeing here. Therefore, since she is already showing breathing changes, we need to be proactive and start taking diagnostic steps to determine which is to blame for her signs. If you narrow down the differentials but cannot identify a cause (ie if its one of those more subtle ones or is lurking in the lungs), then it would be ideal to follow up with your vet. Especially because your vet will help you treat but also identify the agent present. And that will let you ensure you are treating her as effectively and economically as possible and giving her the best chance of recovering.
Just in case you do need an avian vet and do not have one already, you can check where you can find one at near you at AAV (http://www.aav.org/search/), Avian web(http://www.beautyofbirds.com/recommendedvets.htm) or Birdsnway(http://www.birdsnways.com/birds/vets.htm).
Please take care,
If you have any other questions, please ask me – I’ll be happy to respond. **Please rate my service afterwards, as this is the only way I am credited for helping you today. Thank you! : )