How hours is a salary Execuative Director of a small 3 employee nonprofit orginazation work, required to work?

This small non profit orginaziton has a executive director and two part time employees. Two of her friends on the board are insisting the director get a $500.00 Christmas bonous because she is sometimes required to work over 40 hours per week. This orginization survives by fund raisers, donations and seldom grants and is usually very low on funds..