Talk to Guru Guru(The guy with the music box thing) at 1st or 2nd night as Hylian Link and he'll give you the Bremen Mask. Then on the Final day head to Romani Ranch(Southwest of Termina Field), and head to the Cucco Shack. There put on the mask and start marching around so the chicks follow you. Hold B 'til you get all of them, then they grow up. Talk to the guy sitting there to claim the Bunny H