You may well already know this, but the separate words for meat and animal are likely because of the Normans; the richer French speakers cooked and ate the anim

You may well already know this, but the separate words for meat and animal are likely because of the Normans; the richer French speakers cooked and ate the animals, so they got French names; the poorer "English" raised the animals and called them by their English/Germanic names. We do have a word with a French root for chicken, by the way: poultry. As to why the separate name didn't catch on, I can only speculate that it's because chicken are cheap to keep and so the English may have eaten them themselves. Not all languages have separate words for meat - German perhaps being the most famous. It's slightly disconcerting to walk around a supermarket and see schweinefleisch being advertised.