What is a "nest house" in the context of a shared custody after a divorce in Spain?

The “nest house” system is a way of organizing the exercise of shared custody between two parents.

After the breakup and the divorce, the parents cease to live together and, therefore, there are two options in relation to the exercise of said joint custody: that each of the parents resides in a home and that the minor is the one who moves for alternating periods or that parents alternate the use of the family home without the minor having to move.

And, that second option is known as "nest house": that the minor does not move from the home.

Fundamentally, and historically speaking, at the beginning of shared custody concessions, it turned out to be an option that many Family Courts opted for.