We study a spatial birth-and-death process on the phase space of locally finite configurations Γ`ˆΓ´over R d . Dynamics is described by an non-equilibrium evolution of states obtained from the Fokker-Planck equation and associated with the Markov operator L`pγ´q`1 ε L´, ε ą 0. Here L´describes the environment process on Γ´and L`pγ´q describes the system process on Γ`, where γ´indicates that the corresponding birth-and-death rates depend on another locally finite configuration γ´P Γ´. We prove that, for a certain class of birth-and-death rates, the corresponding Fokker-Planck equation is well-posed, i.e. there exists a unique evolution of states µ ε t on Γ`ˆΓ´. Moreover, we give a sufficient condition such that the environment is ergodic with exponential rate. Let µ inv be the invariant measure for the environment process on Γ´. In the main part of this work we establish the stochastic averaging principle, i.e. we prove that the marginal of µ ε t onto Γ`converges weakly to an evolution of states on Γ`associated with the averaged Markov birth-and-death operator L " ş Γ´L`p γ´qdµ inv pγ´q.