Simple:
* Fox flouts fence.
* Fox feeds fercely.
* Fox forages for food.
More creative:
* Fox flitting fast through fields of flowers.
* Fox feigns friendliness, for food's fake.
* Fox famous for frustrating farmers.
Humorous:
* Fox finding friends for foolery.
* Fox fumbles for fruit, falls flat.
You can use alliteration to create a variety of effects, from simple and descriptive to playful and humorous. Just remember to keep the words you choose relevant to the context of your writing.