Vaccinations

Personally, and this is just my opinion, that vaccinations or no vaccinations it doesn't really make a difference to a back yard keeper.

The only thing you should keep in mind is that you shouldn't mix vaccinated and non-vaccinated hens, as the vaccinated ones can still be carriers of the illnesses they have been vaccinated against.

The majority of back yard owners aren't going to face the illnesses that farmers face when huge numbers of hens are kept in one static place; conversly the one disease (Mycoplasma) that back yard keepers do see a lot of, most small scale breeders wont vaccinate against becasue the vaccine is so expensive, and has to be be administered by injection.

Most of the infections birds pick up cannot be passed to humans.  In the case of salmonella you just need to make sure that any egg or meat products are cooked thoroughly as salmonella is killed at high temperatures.

Personally I haven't heard of anyone who has been sick with salmonella after eating "home grown" eggs

Even if a bird has been vaccinated that's not necessarily a good thing.  Not all vaccinations are equal.  It depends on the type of vaccine.  

Live vaccines are quick and cheap but they may leave the bird a carrier though immune.  Not a problem when it's part of a closed community who are also all vaccinated to be immune but not so good if you then take them out of that closed community and put them in a healthy but unvaccinated community.  Which is exactly what happens with many ex batts.  There are other types of vaccines which don't involve live strains but they are less attractive for the commercial farmer as they are usually more expensive and take longer to build immunity.  Try asking your ex batt rehab charity what vaccines the birds you are about to take delivery of have had and see how far you get in getting answers  

The commercial 'all in, all out' vaccinated stock system of husbandry is designed to prevent disease spread between generations and it works but rehoming ex batts breaks the closed system.  Even with hybrids reared for the backyard market you need a knowledgable keeper who understands the issues of vaccination.  I suspect not many do.  Personnally I think if you have any vaccinated stock all your birds need to be vaccinated.  Thats very difficult to achieve if you mix pure breeds obtained from enthusiast breeders with hybrids from commercial growers and ex batts.  Most of the time no doubt you will get away with it but don't assume vaccination is the answer to good healthy stock.

HF