Unlike most languages English has specialized terms for the meat of particular animals, deriving from the Norman conquest of England in 1066: while the animals retained their English names, their meat as brought to the tables of the invaders was named in Norman French. These names came to be used by the entire population.
So the English peasants would raise and slaughter a cow , and the French lords would eat the beouf. The peasants raise a pig, the French would eat the porc. And by the way, the English would raise a sheep, but the French would eat the mutton.
Chicken, however, was a very cheap meat that even peseants could afford, so the English word remained more popular although poultry had its origins in pouletrie apparently