Find all rational zeros of the given polynomial function.
\[
h(x)=x^{4}-11 x^{3}-154 x^{2}-421 x-255
\]
The rational zeros are
(Simplify your answer. Use a comma to separate your answers as needed. Type an integer or a fraction.)

Step 1 ：The given polynomial function is \(h(x)=x^{4}-11 x^{3}-154 x^{2}-421 x-255\).

Step 2 ：The Rational Root Theorem states that the possible rational roots of a polynomial equation are given by the factors of the constant term divided by the factors of the leading coefficient.

Step 3 ：In this case, the constant term is -255 and the leading coefficient is 1.

Step 4 ：So, we need to find all the factors of -255 and divide them by the factors of 1. The factors of -255 are [1, -1, 3, -3, 5, -5, 15, -15, 17, -17, 51, -51, 85, -85, 255, -255].

Step 5 ：Then, we need to substitute these possible roots into the polynomial to see which ones are actually roots.

Step 6 ：After substituting the possible roots into the polynomial, we find that the rational roots are -3 and -5.

Step 7 ：Final Answer: The rational zeros of the given polynomial function are \(\boxed{-3, -5}\).