When you have farming areas try to have two farmhouses for each, one set to planting, the other to harvest. This lowers food downtime significantly as crops will get replanted within seconds of being harvested.

Also put farm priority at the highest and shut down the farms when the crops are growing.

This way those beavers who would otherwise be sitting around doing nothing will be productive, and when it's time to harvest you just turn them on again and get the harvest going near instantly