how to feed guinea pig for 3-4 days while i'm away?

Simple answer - NO! There are way too many things that can go wrong. 24 hours is the absolute maximum you should ever risk. Even with extra feed and bottles disasters can happen. Bottles leak or jam, crocks get tipped or soiled, pigs do stupid things and hurt themselves, pigs get sick etc. Every bottle we ever had fail (and we've had plenty in 40+ years) worked fine until it didn't!

If you value your pigs health and safety you MUST have it attended to daily either by having someone come in or boarding it with a sitter or a vet.

Its not a good idea as you should never leave ginnys by them self or any other animals For that matter they are like Kids, you would”nt leave Kids behind. If you cant get any one to watch to her then you should not go on your trip. Ginnys need fruit, and veggies every day plus their hay. ginnys need ppl and a play mate(same sex).after 12 hrs gininea pigs can die if they dont have enough food.

Hm... it's honestly not the best idea to leave him alone for so long. If you absolutely can't find anyone, then just be sure to fill up his pellet dish to the top, as well as his timothy hay to the top. Maybe put an extra pellet dish in there.

How fast of a drinker is he? You don't want him to go without water for more than a day. If you only have one guinea pig, a full water bottle should last him maybe two days, depending on how fast he drinks.

But seriously, try to find someone who can take care of him, even if it's just one of your neighbors. They can just go in there once while you're gone and fill up his food and water, it'd really be for the best.

You should not leave your pig alone for that long, you're supposed to feed your pig their pellets, veggies and fruit daily. So if you are going to be gone for that long you should have someone come and check up on your piggy.

Give him lots of hay.