Costs money!

Is the vaccine patented?

If not, someone ought to be able to make a big spinning needle-wheel to vaccinate chicks at a rate of 10 per second from a big bucket of vaccine.

If there's a patent, you can bet it'll be billed at a couple of dollars per dose, which is totally infeasable when 1 cent per chick can be the profit margin.

The vaccine costs $0.01 per chicken. And no, that's not a typo. Labor is a bit more, but not much - it's done in bulk by spraying it.

Buy some here: https://www.valleyvet.com/ct_detail.html?pgguid=FBE23AC3-EB6...

$41.40 for 5,000 doses.

Actually still sounds quite expensive... Like that's more than the cost of the drinking water or electricity for lighting for the whole life of the chicken...

But that's not how you do cost benefit analysis. If the cost to vaccinate a chicken is one or even several cents per chicken, then you're calculating the price offset based on the total yield of that chicken, i.e. the eggs that chicken produces.

Production chickens have a one day laying cycle, so you get about an egg a day, for about a year before production drops off to less than that. So that's 5 cents on a minimum of 350 eggs (more if the chicken is kept despite production drop-off), which would be a staggeringly irrelevant price increase per egg if vaccination would be legislated into being a mandatory practice.

Which it should be.

Years ago.