Sweet Feed or Sweetfeed is a mixture of grains with molasses. Sweet Feed is the name of a grain mixture used to feed horses and other livestock. The combination of grains and molasses makes a great grain bill for Whiskey. Premixed Sweet Feed bags can be found at Tractor Supply and other similar places. Watch for any extras like pesticides or preservatives. Also avoid the pelletized versions.
Home Mixed All Grain Version
Start with a mix of 30/30/30/10 of corn, oats, malted barley and molasses. The ratios can be changed to your liking, but keep 20-30% of the grain bill malted barley in order to maintain enough Diastatic power to ensure conversion.