So not jumping to conclusion, I may understand what encoreman wanted to ask:
We just started having pets "quails and chickens" for about 2 months now, and will be heading out to our first in a couple of weeks. We will be gone for 3 days and unable to find a free sitter for our pets. While the feeding/water system will hold for more than 3 days, we are still concern about their well being.
As the other posters above me had stated, they are animal/pet/livestock etc.. they should be checked on a daily base when all possible. Injury and accident can happens at any moment.
If you are confidents in your feeding/water system and can remove the injury/accident factor from your mind (basically not worry about them) then they can be left alone as long as there are water/food and a "clean" living area. A "clean" living area maybe your problem. We clean our wired floor cage (5x3x2 feet) with 7 quails once a week, no cleaning is needed really until we can't stand the odor. Our solid floor cage with 7 quails require cleaning every 5 days at most, but we do clean it daily since we do not want poopy eggs.
To answer your question directly, to me, my currently system can last up a week at most before I'm super concern due to their droppings.