A vaccine for chickens exists, that was never required because it would restrict exports to certain countries; hurting profits.

Now we have permanent reservoirs of the disease in cattle and wild birds.

Note that Biden did allocate 1.8B in funding to deal with birdflu in humans over his 4 years.

So basically we had the Biden admin coasting as boat passes the point of no return so as to not upset the capitalists short term profits, and Trump taking over and paddling directly towards the waterfall.