The production fractions of B̄s0 and Λb0 hadrons, normalized to the sum of B- and B̄0 fractions, are measured in 13 TeV pp collisions using data collected by the LHCb experiment, corresponding to an integrated luminosity of 1.67 fb-1. These ratios, averaged over the b hadron transverse momenta from 4 to 25 GeV and pseudorapidity from 2 to 5, are 0.122±0.006 for B̄s0, and 0.259±0.018 for Λb0, where the uncertainties arise from both statistical and systematic sources. The Λb0 ratio depends strongly on transverse momentum, while the B̄s0 ratio shows a mild dependence. Neither ratio shows variations with pseudorapidity. The measurements are made using semileptonic decays to minimize theoretical uncertainties. In addition, the ratio of D+ to D0 mesons produced in the sum of B̄0 and B- semileptonic decays is determined as 0.359±0.006±0.009, where the uncertainties are statistical and systematic.