The English royal court became french speaking after the normands invaded, around 200 or 300 years ago. Nobles and royalty can afford lavish meals and dishes.
They can also regularly afford meat, whilst it was the peasants who tended to the animals. Thus pork (from porc) vs pig, beef (from boeuf) vs cow, poultry (from poulet) vs chicken.
It doesn’t explainall of the gaps, but it’s an important part of the explanation.