We present results for YbAl$_3$ which show that the susceptibility $\chi(T)$, 4f occupation number $n_f(T)$ and the entropy $S(T)$ exhibit a slow crossover between the Fermi liquid and local moment regimes. In addition both $\chi(T)$ and the linear specific heat coefficient $\gamma = C/T$ exhibit low temperature peaks that imply that in addition to the Kondo scale ($T_K$ $\approx$ 500K) there is a second low temperature scale ($T_coh$ ^M$\approx$ 50K) for the onset of coherence. We discuss these results in the context of Nozieres' exhaustion in the Anderson lattice.