Check out the report of Dave´s frustrated colleague for animal idioms:

Yesterday Dave went totally apeshit, he told me that he´d had with the boss´s harebrained ideas, who was only copycatting the comptetion anyway. I told him to hold his horses, but he just rambled on that he had already signed up with the competition. He was sick and tired of doing all the donkey work for chickenfeed, while the big boss kept the lion´s share. So he would kill two birds with one stone and get the sucker off his high horse and quit this monkey business for good. You ask me if I´m serious here? I´m talking facts here, I´ve got it straight from the horse´s mouth.

explanation:

to go apeshit = total ausflippen,  harebrained = hirnrissig (wörtl. hasenhirning), to copycat = abkupfern, to hold one´s horses = halblang machen, to do the donkey work = die Drecksarbeit machen, chickenfeed = Kleingeld, the lion´s share = der Löwenanteil, to kill two birds with one stone = zwei Fliegen mit einer Klappe schlagen,  to be on the high horse = auf dem hohen Ross sitzen, monkey business = Affentheater, straight from the horse´s mouth = aus erster Hand