Crews are still working on putting out a two-day-long fire.
Residents were advised to keep their windows and doors shut while the haystack fire 'burns out', but have now been told it is safe to have them open.
The site, in Whittersham Road, in Wittersham near Cranbrook, has been alight since Tuesday night.
Firefighters are allowing the blaze to burn out under controlled conditions under a watching brief, which is normal procedure for fires of this nature.
Throughout Wednesday crews were at the scene dragging out sections of hay to dampen it down.
Now, people living close by are advised to keep their windows and doors closed due to the smoke coming from the haystack, which is still burning.
A spokesman for the service said: "People living near to Whittersham Road, in Wittersham near Cranbrook, are advised to close windows and doors due to smoke coming from a haystack fire.
"Overnight it is being left to burn itself out under controlled conditions once again.
"While this happens, varying amounts of smoke will come from the scene."
Over the last few weeks, Kent Fire and Rescue have dealt with several fires on farm land.