Egg production is spreading (6)
I believe the answer is:
laying
This clue could be a double definition.
'egg production' is the first definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'spreading' is the second definition.
The answer and definition can be both to do with contact as well as being present participle verbs.
Perhaps they are linked in a way I don't understand?
'is' is the link.
Can you help me to learn more?
(Other definitions for laying that I've seen before include "Preparing (a fire)" , "Placing" , "Putting in a horizontal position" , "Producing eggs" , "Putting down (carpet)" .)