Count chickens it's a plausible number. If you count things like small fish and shrimp then it's probably a severe underestimate. I guess he isn't counting those, self-described vegans often don't for some reason.

I probably eat a thousand anchovies a year alone.

FWIW I'm actually not a vegan, or even a vegetarian. I eat and thoroughly enjoy meat.

But anyway yes, most of the specific individuals animals killed are chickens and water creatures of various types.

How long can a single shrimp or chicken feed someone?