"The more chickens in a farm the more crap and the fewer eggs"

There's Too many cooks spoil the broth.

Everyone has a hand in the pot, so to speak, and what comes out is inedible.

A Chinese proverb at thinkexist probably comes closest to the intended meaning:

An overcrowded chicken farm produces fewer eggs.

In English, the word “chicken” has no gender attached. Per spanishdict.com, in Spanish we have “gallina (f) (bird); pollo (m) (meat)”. A gallina translation like “The more hens, the fewer eggs” would be parallel to the Chinese proverb. “The more roosters, the more crap and the fewer eggs” has a chance of being true if roosters crowd out hens. (Roosters don't lay eggs.)

Another saying like Too many cooks spoil the broth is Too many chiefs and not enough Indians. This also might apply if roosters have crowded out hens.