Hybrid fall rye is sold by the unit, 1 unit is 1 million viable seeds. Typically farmers target 0.8 of a unit per ac. If the crop is for forage use, organics, or you are seeding late in the fall the use rate could increase. Seed bed preparation is critical as you want the crop to be as even as possible to ensure even flowering timing.
Hybrid fall rye:
Has short strong straw for rye, suitable for irrigation or dry land
Excellent grain quality with plump seeds and excellent falling numbers for rye milling
Hybrid yield potential 20-40% more than traditional rye varieties, preforms well under stress
Amazing potential on dry land and irrigation
Rye has roughy double the root system of winter wheat so can scavenge for water and nutrients
Strong winter survivability
Silage yield potential very high with good quality and early harvest
Some farms double crop by cutting the rye before heading and allowing it to regrow. Others are silaging rye in early July and plant oats following the rye silage.