Why are whales, but not chickens, in danger of extinction?

Even though there are still a lot of whales and chickens out there in the World, why would people say that only the whales are in danger of extinction? After I researched on the internet I found out clearly it is because of that whales can produce normally only one baby whale but chickens can produce more than one egg at least. And it also mentioned that chickens, cows and pigs are not in danger of extinction because those farmers said that they can produce millions of them in every year compared to that the number of whales are decreasing every year!
So, we must stop whaling around the sea! Specially Japanese fishermen!