Tick eggs hatch as 6-legged larvae in the summer of the same year they were laid. They're about the size of the full stop at the end of this sentence.
 

The larvae remain inactive till the next spring, when they climb grass and wait for the first of the 3 hosts they'll need to feed from during their life cycle. Potential hosts may include mice, squirrels, rabbits, birds, deer, livestock, cats, dogs and man.
 

Tick larvae spend up to a week feeding from the host, before they detach and fall to the ground.