randomize text objects position

You could use the wiggle expression on the the Position property. Something like wiggle(5,30) should give you sufficient movement.

The first value determines the wiggles per second, the second value determines the limits of the motion.

Since wiggle is based on the layer's index, duplicating and offsetting the layer will produce enough random motion.

You can also use various particle effects to make items behave as a swarm.

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Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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If you have it, Trapcode Particular can react to a layer defined as a floor or wall.

http://www.redgiantsoftware.com/products/all/trapcode-particular/

You'l need to search for a tutorial that meets your criteria.

Particle Playground (included with After Effects) can use a mask shape as a boundary – also called a "Wall" in the effect control panel for Particle Playground.

You could make the shape of the hive as a mask, define the mask as a wall, any particles emitted inside the mask will bounce off of the walls.