Term to describe the movement in a group of maggots?

I am a non-native speaker.

What would one call the movement of a large group of vermin (not of an individual)?

For instance, picture a huddle of maggots in cat food. How are they moving?

Creeping or crawling came to my mind, but this rather describes the way of moving of a single maggot rather than the chaotic movement of the group.

Crawling can actually be used to describe the chaotic movement of a group of vermin, as in "the old cheese was crawling with maggots."

be crawling with: to be full or completely covered with people, insects, or animals, in a way that is unpleasant.

Be alive with is another idiom that might fit the bill.

The cat food was alive with maggots.

be alive with: to be covered or full of something that is moving

Alternately, consider wriggle and squirm.

Maggots were wriggling all over the cat food.

wriggle: to twist from side to side with small quick movements like a worm

The cat food is teeming with maggots.

Teem: be full of or swarming with.

In the particular case of maggots in cat food, the following come to mind:

The maggots were _____

-writhing, -churning

I'd suggest the maggots, rats, fleas, or whatever might swarm:-

To move or gather in large numbers [American Heritage Dictionary via the Free Dictionary]

or perhaps overrun:-

To spread or swarm over destructively [American Heritage Dictionary via the Free Dictionary]

So you might say the maggots swarmed over the cat food or the rats overran the kitchen.