We need another term besides "vaccine" for the class of inoculations which don't prevent disease spread but rather lessen the (statistical) occurrence of severe illness. A lot of the focus on "vaccines" for chickens, cows, pigs etc. is on preventing severe illness: preventing serious illness still allows product to be delivered to market (hopefully post illness) whereas preventing disease spread requires a commitment to culling breakthroughs which interferes with profit!
My general understanding that preventing serious illness, rather than transmission, is the objective with current influenza vaccines for humans as well.
(As long as they're not noticeably sick, I'll keep on hugging my chickens as a source of generalized immunity to both coronaviruses and influenza.)