The Access Code says:
Deer management can take place during many months of the year but the most sensitive time is the stag stalking season (from 1 July to 20 October, but with most stalking taking place from August onwards).
During this season, you can help to minimise disturbance by taking reasonable steps to find out where stalking is taking place (such as by using the Heading for the Scottish Hills service) and by taking account of advice on alternative routes.
Avoid crossing land where stalking is taking place.
Stalking does not normally take place on Sundays.
Be aware that stalking continues during the hind season between 21st October and 15th February and you should, as always, be prepared to follow reasonable requests.