I love this question and its origin. I, too, would like to know if chickens (and other birds with stabilization) can get seasick!

Ducks get carsick. I had a duck that went for a few car rides and he'd get sick every time. :(

Okay, the caveats. I've never sailed on the ocean. Nor have I taken my birds out fishing. So, no first hand anecdotes, alas.

That being said, chickens aren't prone to motion sickness of any type. And, because of their gyroscope heads, aren't going to suffer the usual disparity between balance/motion sensing organs and visual input that's the big cause of seasickness.

Chickens have been transported by boat all through their history as livestock, with no significant issues directly from being asea/afloat.

So, overall, even if they aren't totally immune to some degree of difficulty with water travel, it wouldn't be seasickness, but some other issue with similar symptoms.

Both of my birds have travelled by car multiple times. Our hen used to go visit my sister's household almost daily via car. Zero issues. Can't say anything about ducks, but chickens shouldn't get sick when properly secured in a car

Why are you dreaming unpublished Douglas Adams novels?

Mostly unrelated but my cat never seems to get seasick. In fact her sea legs are superior to mine so long as she stays off the slippery table.

chickens can't vomit.

I would imagine not, for the reason the dude claims. Many birds heads act like a gyroscopic stabalizer. I also don't know if their ears have fluid in them like ours do. That fluid is why we get motion sickness. Animals without that fluid probably don't have any problems.

I had a dream once where I was at work and someone mentioned seeing a chicken on the factory floor. Then someone else mentioned seeing a chicken on the other side of the building. Then one in the bathroom. A little while later it was becoming a little concerning. By break there were so many chickens that the forklifts had to drive slower. Not long after, there were so many that people were sheltering in closets and various small cubbys and such. The lucky ones made it outside before people suffocated from the sheer volume of chickens.

Im sure sailors keep chickens or at least some egg laying bird that can eat scraps.

Ducks and other water fowl hang out on the water’s surface, I bet there is some truth to this but I am not an ornithologist.