I don't. I do sometimes leave for a few days, but my wife then picks up the slack.
That said, I **DO** have a pair of gravity fed, rainwater filled, 275 gal totes which provide water to my birds, so that's automatic, whether I'm here or not. and even if one fails, the other still works, so that's a concern I just don't have. Even three weeks of drought won't run one completely empty at the rate my flock consumes water. Four weeks might push the limits of a single tote.
I also have "J" style gravity fed feeders **WHICH I DO NOT USE**. If I were vacationing, I'd fill all three with pellet (crumble doesn't work in these, for a host of reasons) - that's more than 50# of food, good for maybe 5 days, perhaps 6 - and leave them stuck in their 900 sq ft run. and hope. When my wife is watching, she, like me, feeds about 3# (dry weight) of fermented mash each day, more in winter, and lets them free range any day its not raining cats and dogs.
I have one good neighbor I'd happily pay in dozens of eggs - or cash - but eggs would be better, to do the same, and I'd leave her a handful of 5 gallon buckets of ready-made mash for her use (I blend feeds from the local mill to get the protein % I want at decent price)