She very well might not like living with other cats, but there are ways to make the situation more tolerable for her. When did you get the other cats, and how did you do the introductions?
What are the ages of all your cats?
Do you have any tall cat condos or shelves for the cats to climb and hang out on?
When was Bianca declawed? Are the other cats also declawed?
Please don't take her to the Humane Society, that could very well be a death sentence (kill rates for cats in shelters can be as high as 90%). There are ways to deal with this situation without jeopardizing her life. You may have to work at helping the cats get along, with things like play therapy using interactive toys, enriching their environment with plenty of vertical territory, and changing their living arrangements (litter boxes in multiple areas, space for Bianca to have down-time away from the other cats, etc).
Also, what do the cats eat right now?
"To close your eyes will not ease another's pain." ~ Chinese Proverb
“We must not refuse to see with our eyes what they must endure with their bodies.” ~ Gretchen Wyler