Here are some tips on how to use, build and maintain horizontal silos and also on how to "renovate" old, unlined trench silos for use "as is" or for use in self-feedings in much the same manner as horizontal silos.
Van Vlack, C. H.
"How To Use, Build, and Maintain Horizontal Silos,"
Iowa Farm Science: Vol. 8
, Article 6.
Available at: https://lib.dr.iastate.edu/farmscience/vol8/iss2/6