Vets or apple cider vinegar ????

vets it sounds like an infectious respiritory infection and they will all need antibiotics.

When you say bird trust, without naming names I think mine came from the same place (this is last year). I had 2 hens, one I suspect was a month or so younger than the other and I think she got really stressed from the journey, new environment and the fact the was immediately put in the bottom of the pecking order. She appeared distressed (tail down and just not looking very happy but eating & drinking) and I rang them and it was suggested I gave them aloe vera juice. She then developed some mycoplasma type symptoms but it never seemed serious enough to take her to the vets and when she started laying she recovered completely.

The other hen then developed slight symptoms but she also recovered by herself.

I am not sure what the aloe vera juice is supposed to do (I haven't used it since and it didn't seem to help) but people do recommend apple cider vinegar as they say it helps break down any mucus. I have to say that I tried this as well but it didn't seem to work either.

Keep a close eye on them and if in doubt take her to the vet. Hope she gets better soon.

her comb 

The one with the rattly chest in particular needs to go to the vet.  This could be quite a serious respiratory infection, so the vet needs to do a proper diagnosis and will probably prescribe antibiotics, either just for her or for the whole flock.

I don't know how the bird trust people thought apple cider vinegar would help a respiratory infection?!  That seems quite an odd piece of advice to me.

If a chicken is just a bit sneezy, then keeping her warm and making sure she has plenty of good food and water may allow her immune system to fight off an infection by itself.  But once the chest is rattly she needs proper medical care.

I'm affraid this just about sums up my opinion of such people.  Most of them simply haven't the first idea about chickens and the diseases they carry.  They just hand them to unsuspecting backyard keepers willy nilly spreading infections to other chickens.

Frankly far from being good samaritans they are a menance.

Cull the rattly chest one who will never be any good and will be a source of infection to other birds.  Treat the sneezy runny nosed ones with an antibiotic such as Baytril or Tylan and any which don't respond cull.  Any that recover keep separated from other birds and never breed from them or pass them on to anyone else.

HF

Apple Cider vinegar is more of a Preventative than a cure, Same for Garlic, the vitamins and minerals and other goodies can help to boost the chickens Immune system, and thus HELP to prevent colds Etc, Not totally Stop them and not cure them.

Once they have a cold Etc, then its a case of Antibiotics or as the other two above stated, Cull.