The usefulness of a manure depends on how the animal digests its food and the way it excretes it.
Cows are ruminants with a 4 chambered stomach so that they are maximally able to extract nutrients from the grass.
Cattle manure is basically made up of digested grass and grain. Cow dung is high in organic materials and rich in nutrients. It contains about 3 percent nitrogen, 2 percent phosphorus, and 1 percent potassium (3-2-1 NPK). In addition, cow manure contains high levels of ammonia and potentially dangerous pathogens. For this reason, it’s usually recommended that it be aged or composted prior to its use as cow manure fertilizer.
Horses don't have a 4 chambered stomach but have a long gut instead. This means more undigested material reaches the manure. Horse manure after composting was ideal for growing vegetables and for growing button mushrooms but the lack of horse manure has meant in modern times that mushroom growers have had to make their own composts mixtures up. Cow manure just doesn't have enough undigested grass in it to sustain mushroom cultivation.
Bird manures are high in nitrogen. This is because birds only have the one orifice to defecate through so their urine is mixed in with their solid wastes.
Chicken manure fertilizer is very high in nitrogen and also contains a good amount of potassium and phosphorus. The high nitrogen and balanced nutrients is the reason that chicken manure compost is the best kind of manure to use. But the high nitrogen in the chicken manure is dangerous to plants if the manure has not been properly composted. Raw chicken manure fertilizer can burn, and even kill plants. Composting chicken manure mellows the nitrogen and makes the manure suitable for the garden.
Sheep dung is often sold as sheep pellets which acts as a slow release fertiliser. It can be used as a mulch. It is not as high in nutrients as chicken manure so won't burn your plants. Many of my acquaintances use sheep pellets for their vegetables since it's easy to handle.
Sheep manure, like other animal manures, is a natural slow-release fertilizer. Nutrients in sheep manure fertilizer provide adequate nourishment for a garden. It is high in both phosphorus and potassium, essential elements for optimal plant growth. These nutrients help plants to establish strong roots, defend against pests and grow into vibrant and productive plants. Sheep manure can also be used as organic mulch. Because of its low odor, sheep manure can easily be used to top dress garden beds. A garden bed that has a high level of organic matter drains well and has a high number of earthworms and soil microbial activity, all good for plants.