Hi SB
Initially I tried water pistol , then hose pipe , shouted at them , then tried the `look` , sheets of ply between runs , 4 antibark collars worked to a degree but they got sore around neck , had a sprinkler system fitted which activated on sound, worked to a degree till they worked out it just sprayed a 4ft diameter so stuck to the corners to bark . Invested in 4 ultra sonic antibark gizmos with little effect, no wonder they were meant for internal use only . Im now on an external ultra sonic antibark system though im still not convinced it has made much diference . A