Grog appears with a mohawk and his love for Cuccos in Majora's Mask. He can be found all three days inside the Cucco Shack at Romani Ranch. Grog is a quiet type, and the only thing he really seems concerned about is his Cuccos.
When Link meets Grog, he talks to Link about the falling moon. Overall, Grog doesn't have any regrets, for he never was very invested in anything. However, the only regret he has was never being able to see his latest batch of cucco chicks grow into roosters.
Link can help Grog's Cuccos reach maturity before the moon fall by using the Bremen Mask. If Link puts the mask on and holds Ⓑ, he pulls out the Ocarina of Time, and begins playing. Along with his music, the Bremen Mask allows Link to march. In order to grow the Cuccos, Link must march past each and every little cucco chick, lining them up behind him single file. Once Link finds all ten cucco chicks, the chicks grow into roosters one by one. Grog feels complete seeing his little cucco chicks grown into adults, and rewards Link with the Bunny Hood for his help.
Grog's only entry into the Bombers' Notebook is receiving the Bunny Hood, which is attainable at any time he can reach Romani Ranch. The notebook describes Grog as a "cucco-lover".