Or they could publish the actual term used so that anybody could check, but they didn't. But they use Beijing written in the characters, as if it was the important part.
NextWeb's reporting on the Twitter thread suggests that the phrase may be a Chinese attempt to translate to English a Chinese word meaning "woman of child-bearing age" [https://thenextweb.com/tech/2019/03/11/1-8m-chinese-women-de...], but we don't actually know because we have no primary source on what character was translated as "BreedReady."
It's not just speculation, the fact is the database is Chinese and the key is "BreedReady". I don't find it that difficult to understand how it could have ended up like that.
It still could be a translation to keep the keys in English though.