> The milk is super creamy and if you boil it for 2-3 times, you get like 1-cm creamy foam on top. I tried the same with Costco whole milk, and didn't get as much cream/richness.

That's probably because supermarket milk is typically homogenised, meaning it's been put through a very narrow funnel with great force until the fat globules break and become more evenly distributed throughout the milk. That's why supermarket milk doesn't have "cream on top". The fat stays suspended in the milk liquid and doesn't rise to the top (as is normal with milk that hasn't been homogenised). Homogenisation also usually standardises milk to a certain fat content while the excess goes to make butter, so you can expect homogenised milk to be just exactly 3.5% in fat (for cow's milk) while the milk you get from your local farmer is going to vary a lot above and below that, depending on season, feed, reproductive cycle and activity of the animals etc.

I suspect that the fishy smell in US chicken is because of a chlorine wash. There was a bit of a scandal about it recently in Britain.