Could be a respiratory infection Azzdodd. Or it could be an inoculation flare-up caused by the stress of moving house (IB infectious bronchitis). Need to observe their poos. Green will be an infection. Worming with Flubenvet is a good idea as they have probably never been done. Good luck with them. They used to sell year old hens near me in Staffordshire at £1 each -think that's good value, as they will have loads of laying life left in them.
Mixing them with your other birds may cause big problems. They will be ILT and IB virus carriers and if they shed the virus and none of your other birds have been inoculated they will all be infected. We had this problem and had three very stressful weeks nursing the flock back to health. Didn't lose any but 4 years on and our cockerel still gets ILT flare-ups.