We are registered with animal wealfare. They have never mentioned an immunisation programme and I would not recommend it. Some vaccines are live (IB, ILT), put in the drinking water. It makes them infectious to any untreated birds and the older ones you have may not be able to cope. Generally only hybrids are immunised, Pedigrees are not. Pedigrees don't need to be treated as they are reared in small numbers in far better conditions. Hybrids are the opposite, bred in large numbers on a Commercial basis. For this reason I would alwys advise against mixing hybrids and Pedigrees. We got caught our with it and introduced IB and ILT simultaneously into our Pedigree flock. Stressful and expensive time for us.