In my childhood, my sister spoke out and she got what she wanted. My brother kept quiet and he got what he asked for (nothing). I was the youngest and I got a lot without needing to raise a fuss.
This is one of the most blatant rules you learn when you come from a big family. If you make a lot of noise about something you want you’ll get it. If you don’t nag and scream about what you want, chances are you won’t get it.
I have two sibilings who pretty much get everything. That’s because they know exactly how to emphasize the extreme importance of their needs. They know how to nag you and have a thousand ways and rules to make it sound so incredibly easy for you to get them what they want. Yesterday we ran out of ink in the printer. I simply e-mailed the papers I needed to myself, then went to the library and printed out the papers. When my sister got home from school she managed to get my mother to take her to Save-on to get a certain type of Shampoo which she "desperately needed." On her way to doing errands, she also got my mother to go to Staples and get a new ink cartridge. I don’t believe that some kids in a family are more spoiled than others because the parents spoil them more. It has more to do with the kids than the parents. Children who are naturally quieter and don’t enjoy noise and making scenes simply won’t get everything their noisier sibilings get.