I thought Pace meant Easter (the same same as Paques in France, and the Paschal Lamb).
In the middle ages eggs (being an animal product) counted as meat, so couldn't be eaten in Lent. You ate up all your eggs on Shrove Tuesday (Mardi Gras/Pancake Day).
But the hens didn't stop laying. Instead of throwing these eggs away, you hardboiled them and could use them after Easter - for food or fun as the whim took you.