To reduce human impact upon the environment, a transition from fossil to renewable energy sources such as biomass is imperative. Biomass from animal waste such as horse manure has unutilized potential as it has yet to be implemented at a large scale as an energy source. Research has demonstrated the technical feasibility of using animal waste for energy conversion, though their supply chain cost poses a barrier, as does a gap in research regarding the specific design of efficient horse manure-to-energy supply chains. In response, we investigated the design of horse manure-to-energy supply chains through interviews and site visits at stables, as well as through interviews with transport companies. Our findings show that horse manure-to-energy supply chains have distinct attributes at all stages of the supply chain such as the geographical spread of stables that determines supply chain design and hampers efficiency. They share several such attributes with forest biomass-to-energy supply chains, from which important needs can be identified, including the industrial development of trucks dedicated to the purpose, mathematical modeling to handle the trade-off of cost of substance loss in storage and cost of transport, and business models that reconcile the conflicting goals of different actors along the supply chains.