The kids had to fend for themselves while their parents were away.
fend somebody/something offphrasal verb
to defend yourself against someone who is attacking you [= fight somebody ↔ off]:
Tabitha threw up an arm to fend her attacker off.
to defend yourself from something such as difficult questions, competition, or a situation you do not want to deal with:
She uses her secretary to fend off unwanted phone calls.
The company managed to fend off the hostile takeover bid.