Dependent on troop build a skunked level 6 e barracks can eat upto 1300 battle horses a day, also some players like to produce extra and sell them on TO. So a level 6 e stable x2 buffed wont provide enough horses to run your barracks at times. Where the OP has worked out the 3.5 x the amount used barracks i have no idea so again whats the issue ?