How many letters does the top answer for “the science of eggs in relation to their coloring, size, shape, and number.” have?

The most common answer is ooelogy (7 letters).

Crossword clue: the science of eggs in relation to their coloring, size, shape, and number.

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

ooelogy 7 letters web-def

The science of eggs in relation to their coloring, size, shape, and number.

oology 6 letters web-def

the branch of zoology that studies eggs (especially birds' eggs and their size, shape, coloration, and number)