As Elizabeth said the vaccine is for birds that are at least 7 weeks away from POL at the time of first vaccination! And Missy since it is chicks that are at most risk, and I can't find any information on if the eggs are safe to eat after vaccinating, I would not vaccinate the older hens until you can find info on how long you have to wait to consume the eggs from your girls after doing so.
So I vote for next weekend even though I have quite a few chicks that will not be old enough for their first dose yet. I am trying to squeeze all the Polish and the 2 other sets of older chicks into the time frame before they get too close to POL to administer safely.
That works for me. Are we meeting in one spot and giving injections, or is the bottle going to travel? If I'm not vaccinating hens, I can put all the little kids in the dog kennel and travel wherever I need to go. And I have a morning client until 10am, but I figured not everyone is willingly up doing stuff that early anyway. Not in our house, at least.
And since I intend to rotate my flock out and rehome hens that aren't at peak laying, there's less at risk if they get infected. (Other than another royally stressful decontamination routine.)