Cow = Vaca, Calf = Becerro, Chicken = Gallina, Horse = Caballo, Pig = Cerdo, Yellow Chick = Gallina amarillo.
Comparatives with adjectives is just an adjective but something more so instead of Good in English you would say execellent.
The Cow is grande. Using the Comparative adjective for grande you would say, La vaca es mayor que el gallina armarillo. (The cow is bigger than the yellow chicken.)
