  We study the global existence and uniqueness of weak solutions to kinetic
Kolmogorov-Vicsek models that can be considered a non-local non-linear
Fokker-Planck type equation describing the dynamics of individuals with
orientational interactions. This model is derived from the discrete
Couzin-Vicsek algorithm as mean-field limit \cite{B-C-C,D-M}, which governs the
interactions of stochastic agents moving with a velocity of constant magnitude,
i.e. the the corresponding velocity space for these type of Kolmogorov-Vicsek
models are the unit sphere. Our analysis for $L^p$ estimates and compactness
properties take advantage of the orientational interaction property meaning
that the velocity space is a compact manifold.
