How to retain Staff during down times in the operation

Hi all,

I am the Chef of a Kosher catering company in Maryland. When we are busy we do parties 50 to 1000, multi-day conferences from 500 to 2500 for 3 meals a day, and deliveries. When we are slow we are slow one delivery here and there and small party for 60 or 100. No Need for the full staff we all just multitask and move on. My question is how do you retain a staff when you are lean??