[jmystro]

Structure is genetic. You can influence structure by manipulating certain hormones though. One way to induce foxtails early would to be done by using bloom boosters with biostimulants that signal the plant to mature too soon. If done too soon, bud sites will stretch to fill in causing calyx foxtails. Stable genetics will not herm but light leaks will cause vegetative foxtails to form out of calyx as it tries to reveg.