  We present a comprehensive set of elastic and inelastic neutron scattering
measurements on a range of Fe-doped samples of U(Ru$_{1-x}$Fe$_x$)$_2$Si$_2$
with 0.01~$\le~x~\le$~0.15. All of the samples measured exhibit long-range
antiferromagnetic order, with the size of the magnetic moment quickly
increasing to 0.51~$\mu_B$ at 2.5\% doping and continuing to increase
monotonically with doping, reaching 0.69~$\mu_B$ at 15\% doping. Time-of-flight
and inelastic triple-axis measurements show the existence of excitations at
(1~0~0) and (1.4~0~0) in all samples, which are also observed in the parent
compound. While the excitations in the 1\% doping are quantitatively identical
to the parent material, the gap and width of the excitations change rapidly at
2.5\% Fe doping and above. The 1\% doped sample shows evidence for a separation
in temperature between the hidden order and antiferromagnetic transitions,
suggesting that the antiferromagnetic state emerges at very low Fe dopings. The
combined neutron scattering data suggests not only discontinuous changes in the
magnetic moment and excitations between the hidden order and antiferromagnetic
phases, but that these changes continue to evolve up to at least $x$~=~0.15.
