@Tesla;
@FlamingSquirrel;
https://www.quora.com/What-does-吃鸡-mean-in-Chinese
I'll just copy-paste one of the answers to save your time:
It comes from the game “PUBG”. The winner will get his congratulations, saying “winner winner, chicken dinner” (大吉大利,今晚吃鸡).
吃鸡=Eat chicken dinner. Thus, just a celebration.
For PUBG players, the meaning of “吃鸡” is close to “play the PUBG” or “win”. F.e, if you ask your friends “Do you want 吃鸡 with me?” It means “Do you want play the PUBG with me?” Or “Today I 吃鸡了”, it means “Today I got the No.1 in PUBG”.