That is, on any project, if too many people give orders, the project will fail. Searching for this phrase turns up many references to a short parody video. I tried my search by adding -parody -infomercial.
rollsoffthetongue notes variations such as “too many cooks spoil the… soup, broth, or stew.” They say “this is a very old saying or proverb that exists in many languages. In English, it dates back to at least the 16th century when it first appeared in print,” but do not list the citation.
Phrase Finder lists the phrase as originating in another language but, alas, offers no details.
dictionary.reference.com agrees “it was already considered a proverb in 1575.”
RF_alum and I were discussing this phrase when I complained of contradictory comments in a critique of a novel I’m working on. On the plus side, if comments are contradictory I feel justified in doing whatever I want.