My package bees on foundation are on their second box. I still have feeder pails on. The bees will not make foundation unless there is a nectar flow. Even though I have a flow I will keep the feeder pail on until July 1.
Failure to keep the feeder pail on can lead to swarming or a slower build up.
The bees population is larger now. The bees will draw out foundation faster. It is important to keep an eye on the boxes. Boxes can get drawn out quickly. A week can bring significant changes.