  We have obtained high dynamic range, good natural seeing i' images of BL
Lacertae objects (BL Lacs) to search for the AGN host and thus constrain the
source redshift. These objects are drawn from a sample of bright flat-spectrum
radio sources that are either known (via recent Fermi LAT observations)
gamma-ray emitters or similar sources that might be detected in continuing
gamma-ray observations. All had spectroscopic confirmation as BL Lac sources,
but no redshift solution. We detected hosts for 25/49 objects. As these
galaxies have been argued to be standard candles, our measured host magnitudes
provide redshift estimates (ranging from 0.2--1.0). Lower bounds are
established on the redshifts of non-detections. The mean of the fit redshifts
(and lower limits) is higher than those of spectroscopic solutions in the
radio- and gamma-ray- loud parent samples, suggesting corrections may be needed
for the luminosity function and evolution of these sources.
