Had the question from a friend the other day about certain manures and I had to think and even looked one of them up in order to ensure I had the correct answers. So the question is how come some manures are used on gardens and some manures are typically not. The question was specifically what about cat or pig manures and there was a base assumption that chicken (or domestic fowl of any sort) was generally to hot with nitrogen to use readily.
Reality is this, most all manures from animals in all but a very minor application is going to be way to “hot” to apply directly to garden plants. By hot I mean that chemically they will burn the plants and cause more damage then they will good in most all direct applications when coming straight from the collection point of the animal, be it a pan beneath rabbits or a mucking a stall beneath an animal. Reality is in most applications, a mixture of manure with things that are higher in carbon like wood chips or straw, in a compost pile and allowing it to do it magic over a year or so is the best option.
I have read somewhere, several times over, that rabbit manure is the one case that may be applied directly. Of course I have also heard, at least in certain circles the same about just nearly every other manure. I know when I had rabbits, I was not much in the gardening side of things, but combined with horse manures and other fibers, composted down it did a nice job with some flower beds.
I have also read that you want to generally stay away from manures of carnivores and/or pets. This would clearly be aimed at cats and dogs and applies to even those composted. I think the larger concern is the potential for disease spread, though I have never actually seen that listed as the concern. I think, in reality, it is just a matter of the small amount and the gross factor more then anything. Especially when you consider, that while pigs are largely feed grains (and when I grow them pastured on green stuffs), they are omnivores and if given a chance, will indeed eat a chicken or anything else.
Two other options that have not really been considered much here. Of the manures that we often do not think about is the green one, where a cover crop of winter rye or some such is sown. At the time of spring plowing it is often a thing grass. This is plowed under, being the bottom of where the plow turned the furrow next to its current work. This material will usually decompose releasing nice nutrient content into the soil. The second, though with some controversy on the timing, is to graze animals over the area that is to be plowed and let the natural droppings form a nice manure. The trick is the timing though, most recommend a year between the last point animals are grazed prior to planing food stuffs for human consumption. Given that is being plowed under I think letting grazing occur up to the fall before is probably sufficient and know of a cases where it is even shorter. Again, a compost pile spread is similar, but has the rapid breakdown of things going on.
Regardless, any of these are a lot more green then buying chemical fertilizer, excepting under extreme conditions of a major requirement. Keep in mind the chemical fertilizer not only has potential run off problems, but generally it requires a HUGE amount of energy to produce it in the first place.