Guinea pigs can't breathe through their mouths, so any obstruction of the airways is usually noticeable. As bacterial respiratory tract infection (URI) can kill and can in some cases difficult to clear (which could cause long term problems), your vet will first and foremost treat for URI to make sure that this can't happen. Only if issues continue to persist will he look at other options, like allergies.
Since both of your piggies have had crackly breathing, and not just one, and the antibiotic has cleared up your companion's issues, it is more likely to be caused by a URI, but needs another round of AB. Only if that doesn't do the trick should you look at alternatives.
Please do not home treat on spec with over the counter products; that can do more harm than good, and at the worst can lead to death.
Not all URIs are equally severe; some virulent strains can kill very quickly before an antibiotic can kick in, others can be present for a long time without causing any major symptoms until the immune system takes a dive and strike then, often with devastating consequences. Depending on the strain, guinea pigs can survive URI (untreated or undertreated), but it can cause permanent damage, like scarring in the lungs or it can lead chronic lung disease later in life. It is not quite as easy and straight forward as the general information out there, which is putting the emphasis on prompt treatment to save lives makes out.
My old lady Ffraid, who came here at 4 years old, ended up with upper and lower lung disease because of a URI that was not treated long enough when she was young. She had crackly breathing on and off, but it took me two years and a very experienced vet with a very good stethoscope to finally make a firm diagnosis.
I second
@helen105281 in asking for bisolvon powder or a similar mucus thinning product if your vet find that the airways are somewhat or stubbornly congested.
You can also place a bowl of steaming water next to the cage to help ease the breathing.
PS: As we have members from all the world, you can help us a lot by adding your country, state/province or UK county to your details, so we adjust any advice straight away to your climate (which can influence any breathing issues and some illnesses), available brands, vet and rescue access etc. instead of having to keep it as general as possible. Bisolvon is for instance a UK product.
Click on your username on the top bar, then go to personal details and scroll down to location. Thank you!
