Too many people trying to control, influence, or work on something, with the quality of the final product suffering as a result. A shortened version of the full phrase, "Too many cooks spoil the broth/stew/soup." A: "We've got my boss, his boss, the assistant manager, a freelance consultant, and the head of IT all involved, and it's turning into a complete disaster!" B: "It sounds to me like there are too many cooks."