Laura,
I usually do N/B in the Fall. I\'m like John in that I cull and determine who I\'m feeding through the winter, etc. It is VERY easy to do.
Just make sure that you do not have any disinfectant in/on your waterer when you do it as it will kill the good critters the birds need to innoculate themselves.
One thing to keep in mind is that this does not protect the birds from every form of Newcastle. I can\'t remember exactly how many there are, but there are quite a few strains carried by wild birds. While you cannot vaccinate for ALL the Newcastle, having a flock vacinnated will give them better immunity to fight off most forms and certainly give them a better chance than nothing.
When California had a Newcastle outbreak a couple of years ago, our county\'s health people advised making sure poultry flocks were protected with basic Newcastle. Arizona is not a big poultry producing state (commercial-sized operations) so sometimes it is very hard to find out what to vaccinate for.
We have a joke around here that everything comes from Southern California - movies, rain, people getting out of CA and poultry diseases.
Have a good one!
Kathy
Flagstaff, Arizona