  We establish the low-temperature phase diagrams of the spin-1/2 and spin-1
Kondo lattice models as a function of the conduction-band filling n and the
exchange coupling strength J in the regime of ferromagnetic effective exchange
interactions (n ~< 0.5). We show that both models have several distinct
ferromagnetic phases separated by continuous Lifshitz transitions of the
Fermi-pocket vanishing or emergence type: one of the phases has a true gap in
the minority band (half metal), the others only a pseudogap. They can be
experimentally distinguished by their magnetization curves; only the gapped
phase exhibits magnetization rigidity. We find that, quite generically,
ferromagnetism and Kondo screening coexist rather than compete, both in
spin-1/2 and spin-1 models. We compute the Curie temperatures and establish a
"ferromagnetic Doniach diagram" for both models.
