  Some of the small-scale solar magnetic flux can be attributed to a
small-scale dynamo (SSD) operating in the near-surface convection. The SSD
fields have consequences for solar granular convection, basal flux, as well as
chromospheric heating. A similar SSD mechanism is expected to be active in the
near-surface convection of other cool main-sequence stars, but this has never
been investigated. We aim to investigate changes in stratification and
convection due to inclusion of SSD fields for F3V, G2V, K0V and M0V spectral
types in the near-surface convection. 3D magnetohydrodynamic (MHD) models of
the four stellar boxes, covering the subsurface convection zone up to the lower
photosphere in a small cartesian box, are studied using the \textit{MURaM}
radiative-MHD simulation code. The SSD runs are compared against reference
hydrodynamic runs. An SSD is found to efficiently produce magnetic field with
energies ranging between 5\% to 80\% of the plasma kinetic energy at different
depths. This ratio tends to be larger for larger $T_{\mathrm{eff}}$. The
relative change in density and gas pressure stratification for the deeper
convective layers due to SSD magnetic fields is negligible, except for the
F-star. For the F-star, there is a substantial reduction in convective
velocities due to Lorentz force feedback from magnetic fields, which, in turn,
reduces the turbulent pressure. SSD in near-surface convection for cool
main-sequence stars introduces small but significant changes in thermodynamic
stratification (especially for the F-star) due to reduction in convective
velocities.
