Observations during 2013 and 2014 were not moved. This enabled an assessment to be made regarding the how long a carcass could be observed for. This information helps the charity to estimate how many animals may have been killed on a stretch of road over a given time, based on a survey made at a specific point in time.
The negative impacts of leaving a carcass are however unknown. Death of carrion-eaters could be avoided by moving or removing roadkill. Also, it is not known to what extent a person notices roadkill when this is common as opposed to it being a rare event. It is impossible to say at this point whether the removal of roadkill would have an impact on the number of subsequent animals killed on the road and whether that impact would be positive or negative (in favour of the animal).
Another consideration is whether incidents involving domestic animals should be reported, so that their guardians are informed. Consideration also needs to be given as to whether the body should be moved or removed.
There are likely to be a broader set of considerations.