Many people avoid discussion of dung and associated smells and will recoil from any contact with these natural items. Modern culture and custom generally teach that these things are 'taboo'.
In traditional culture animal dung was, and is still, used in a variety of ways - in building construction, fertilisation of crops and as fuel. In the animal kingdom, droppings and smell play a most important role in social and territorial behaviour. While we have been conditioned to avoid contact with faecal bacteria, these same bacteria play a most important role in well-being of most mammals. Even human babies are prone to eating the 'forbidden fruit', let alone dogs and many other animals. Humans without the necessary antibodies have no resistance to disease and illness.
The specific and correct ruminal flora are particularly necessary in herbivores and to this end they need to ingest the droppings of other animals either directly or in water supplies. Without it their digestion would not function. Any unnecessary or excessive material is expelled by a healthy body.
Most of us are aware of the manner in which domestic animals mark their territories and only get upset when they carry on that behaviour in 'our' territories. In natural situations these territorial markings are vital to the social structure and distribution of species. Dominant individuals stake out their required areas with their own particular smell - much the same as humans do with sign posts.
Where communities are established, certain species will set up 'post offices' in the form of middens. These dung-piles serve not only as a place to leave and collect messages but to identify individuals and assess their physical condition. A change in seasonal diet will offer an opportunity to ingest fresh droppings with new bacteria which stimulate the build up of essential, protective antibodies. Most mammals have various scent glands which are intentionally rubbed on objects to mark their passing. It is a silent language available to those with acute powers of smell.
Convenient social rubbing posts are often developed at convenient tree trunks and rocks. One of the main purposes of rubbing is to dislodge ectoparasites, either directly or in conjunction with mud after wallowing. At the same time each individual will leave its smell on the rubbing post for identification by those following - thus providing another 'post office'.
Many well intentioned but ultra-clinical bodies wrongly judge the well being of confined animals by the hygiene of their surroundings. There can be nothing more psychologically damaging to confined mammals than to constantly remove all their faeces and swab out their areas with disinfectant. Recent faeces, if not obviously loose and messy, should be left until replaced by new ones. The glandular rubbing on the surrounds should not be cleaned off. These smells and markings are vital to the well being and confidence of confined animals. Temporary hospital and quarantine areas where disease is being treated are a totally different scenario.
Human health would be greatly improved by the understanding and acceptance that our bodies naturally contain millions of vital bacteria. With the extensive use of broad spectrum antibiotics, we need to replace these necessary bacteria. Your chemist or doctor will advise methods more palatable than those used by animals.