In countries like India people routinely use manure as a fuel for cooking. You can often see people sticking clumps of manure to the walls of houses. The manure conveniently falls off when it is dry and ready to burn. So why can't it work here?
My neighbour has a large muck heap of what could potentially be great fuel. The muck heap is made of horse manure and hemp bedding. Taking the dense black manure from deep inside the muck heap (what gardeners call "black gold"), I cut slices just like you would cut peat. The slices were laid out in a small plastic box full of small holes as you sometimes get in a fruit and veg shop. The holes let the air in to dry the manure. The manure was left to dry under cover for 3 months and I then tried it in a Hunter wood burning stove.
The dried horse manure took a little longer than wood to ignite and once it lit it burnt well if not intensly. The manure gave off a good heat and lasted for longer than I expected - a little longer than cedar, but not as long as oak....Have a look at the video below of the manure burning.
Since horse manure definitely works as a fuel the next step is to come up with some method of storing and drying substantial quantities of the manure. Air will have to be able to get to it so that it dries and it needs to be compact so as not to take up too much room. The method that is used should not take up too much time either - the advantage of free fuel being set against the effort required to process it.