A SWALLOW'S NEST FOR THREE EGGS

I have been watching this pair closely. Their nest is glued with mud onto a stick which was strung up, swing-like, in the old pig sty for a purpose now forgotten. So when the birds land or take off the nest girates for a while. Scary.
She spends a LONG time sat on these eggs - usually more than 30 minutes at a time - and then she disappears for typically three to five minutes for in-flight snacks.
He, meanwhile, spends LONG periods away, and gives her hell if she happens to be off the nest when he returns.
Well, what do you make of that? I wonder if the load is more evenly shared when three pairs of hungry gaping beaks replace these three passive eggs?