Great news
They need a gradual increase through lactation. At this stage the piglets don't take that much but that will change as they grow. A guide is sows daily ration plus pound per piglet by weaning time.
At this stage I find sows either want more or they don't. They sometimes need extra after farrowing but then start to leave some once they feel replenished after the birth and then build up again. If she is leaving extra cut back.
I find with first timers they need more to sustain body condition from earlier on.
Also by the time you get to big feeds they need feeding more than once a day.
As always monitor sow condition.
If you are going to creep feed it takes some pressure off the sow.