Meaning of “BaChiku(バ畜)”

“BaChiku(バ畜)” is a another version of Shachiku(社畜)

Shachiku(社畜) basically means a kind of corporate slave full-time employees, but “BaChiku(バ畜)” means a corporate slave part-time workers.
In this case, “Ba(バ)” is an abstraction for “Baito(バイト)” which means part-time job.

Example Conversation

A: Aren’t you working too much in your part-time job?
B: Yeah, because I’m “BaChiku(バ畜)”.

A: おまえバイトしすぎじゃね？
B: バ畜だからね