  We present low temperature specific heat and ac-susceptibility measurements
on Fe$_{8}$ powdered sample. Below 1.3 K, superparamagnetic blocking effects as
well as an excess specific heat contribution are evident. The latter is
attributed to a splitting of the ground state doublet in an inhomogeneous local
field of hyperfine and dipolar origin. The local field contributions are
evident in the resonances observed in the field dependent ac-susceptibility and
specific heat below 0.5 K. The low temperature Schottky contribution allowed us
to check the crystal field parameters of effective spin Hamiltonians, recently
proposed to simulate EPR and inelastic neutron scattering experiments.
