设\(F\)为抛物线\(y ^{2} =4x\)的焦点，\(A\)，\(B\)，\(C\)为该抛物线上三点，若\( \overrightarrow {FA}+ \overrightarrow {FB}+ \overrightarrow {FC}= \overrightarrow {0}\)，则\(| \overrightarrow {FA}|+| \overrightarrow {FB}|+| \overrightarrow {FC}| =\)______．