The 19-year-old only returned to Vicarage Road last week having spent the past four months with fellow npower League One side Yeovil, for whom he bagged three goals in nine starts and eight substitute appearances.
Massey's first two goals - his first in professional football - came in the form of a brace against the U's at the Weston Homes Community Stadium in a 2-2 draw between the sides in October.
The forward will now work under former Watford striker and first-team coach John Ward, current manager of Colchester.
Massey moves to Essex on a youth loan, meaning the rules regarding a maximum stay of 93 days do not apply.
He is available to make his debut in Saturday's home clash against Chesterfield, the first of six games during his initial stay which ironically concludes with a trip to Yeovil on February 18.









