Imagine three different animals for the farmer:

Set 1: Sheep, Dog, German Shepherd
Set 2: Cow, Chicken (Animal), Pig
Set 3: Duck, Puppy, Piglet

Scribblenauts Remix 1-6 Cheats Hints gallery:
1-6-1-a: Give the farmer three different farm animals!
1-6-1-b: Give the farmer a chicken.
1-6-1-c: Give the farmer a pig.