'Stone age thinking': Dem lawmaker says Trump admin's new policies 'will kill Americans'

Health and Human Services Secretary Robert F. Kennedy Jr.'s suggestion that farmers allow bird flu to spread among their flocks was met with disbelief by Rep. Sean Casten (D-IL), who appeared on CNN Thursday.

The New York Times reported Kennedy's comments on Fox News that farmers "should consider maybe the possibility of letting it run through the flock so that we can identify the birds, and preserve the birds, that are immune to it."

Anchor John Berman began, "One of the things that he suggested was possibly — and he didn't use these words — but, you know, 'let it rip' in a few places, let the chickens pass it on in certain confined areas to see which ones might be immune, so that they can then try to breed the ones that are immune and expand from there. I saw on your Twitter feed you had some criticism over that."

One of Casten's posts read, "This is Irish-Potato-Famine levels of arrogance, stupidity and scientific ignorance."

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"Look, the germ theory of disease is real. Vaccines save lives," Casten said, "and it is hard to process the fact that the the senior health official in the United States is at odds with with the scientific enlightenment. I mean, this is truly stone age thinking."

He continued, "We've seen what happens when you allow diseases to run rampant in societies. I mean, that was the plague, right? The, you know, I think i mentioned on my Twitter, that the Irish Potato Famine, if you do nothing when a blight is spreading that affects a major feed crop, people starve to death. RFK Jr. is going to kill Americans. There's no nicer way to put that. And the most polite way that I can put this is, I am violently angry at the Republican senators who knew everything about what he thought and confirmed him to that position anyway."

Scientists have called Kennedy's suggestion "a really terrible idea," that will kill entire flocks.

Bird flu, known as Type A H5N1, has been reported in humans, although health officials have said, "The risk to the general public from H5 remains low."

Watch the CNN clip below or click here.