  In the present work, we investigate the production mechanism of the
$Z_b(10610)$ and $Z_b(10650)$ states from the $\Upsilon(5S,6S)$ decays. Two
types of bottom-meson loops are discussed. We show that the loop contributions
with all intermediate states being the $S$-wave ground state bottom mesons are
negligible, while the loops with one bottom meson being the broad $B_0^\ast$ or
$B_1^\prime$ resonance could provide the dominant contributions to the
$\Upsilon(5S) \to Z_b^{(\prime)} \pi$. It is found that such a mechanism is not
suppressed by the large width of the $B_0/B_1'$ resonance. In addition, we also
estimate the branching ratios for the $\Upsilon(6S) \to Z_b^{(\prime)} \pi$
which could be tested by future precise measurements at Belle-II.
