A petting zoo in north Wiltshire claims low flying military aircraft are causing its animals great distress.
Studley Grange Farm Park and Zoo near Wroughton said planes flew over its site up to five times per day.
It said the day after a low flying jet passed overhead a ewe had aborted its lamb and a vet said the death may have been linked to the ewe's stress levels.
The Ministry of Defence, which has a site in Amesbury, Wiltshire, said low flying was essential for its training.
Boscombe Down in Amesbury, Wiltshire, is a Ministry of Defence (MoD) aircraft testing site and nearby in Salisbury Plain is a large military training area, from where numerous flights originate.
Farm manager Ms Stewart said: "The lamb had only just died and we think it was a direct result of the airplane coming over so low."
She said the ewe became stressed and would not give birth if it felt endangered, resulting in the lamb dying inside the womb.
John Fishwick from the British Veterinary Association said: "It's terribly upsetting when a sheep aborts.
"There's no doubt low flying aircraft can stress animals and cause problems, the abortion is a possibility.
He said he would recommend a post-mortem examination on the lamb to look for other possible causes of death, before reaching a conclusion.
Ms Stewart said there had been an increase in low flying jets in the past year and it was having a negative affect on its other animals too.
She said the jets caused the goats to frantically jump over fences, it made the rabbits "freeze" in terror and caused the meerkats to "sit shaking" in their houses.
The MoD said it took seriously concerns about low flying.
It said: "The MoD strives to ensure that such disturbance is kept to an absolute minimum and that it is distributed as evenly as possible throughout the UK Low Flying System as a whole."