  We analyze the real photon asymmetry $A^\pm_\gamma$ for the parity violating
(PV) $\pi^\pm$ production on the $\Delta$ resonance via the reactions ${\vec
\gamma} + p \to \Delta^+ \to \pi^+ + n$ and ${\vec \gamma} + d \to \Delta^0 + p
\to \pi^- + p + p$. This asymmetry is nonvanishing due to a PV $\gamma N
\Delta$ coupling constant, $d^\pm_\Delta$. We argue that an experimental
determination of this coupling would be of interest for hadron dynamics,
possibly shedding light on the S-wave/P-wave puzzle in the hyperon nonleptonic
decays and the violation of Hara's theorem in weak radiative hyperon decays.
