How much energy do consumers obtain when they eat

it’s 10%

Explanation: Primary consumers only obtain a fraction of the total solar energy—about 10%—captured by the producers they eat. The other 90% is used by the producer for growth, reproduction, and survival, or it is lost as heat. You can probably see where this is going. Primary consumers are eaten by secondary consumers.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.