Police have launched an investigation into the incident and are seeking information from members of the public.
The incident happened at around 4am on Monday at the Allarburn Farm Shop on Mayne Farm in Elgin.
In a statement on social media, the farm said it would no longer welcome dog walkers at its premises.
Allarburn Farm Shop said: “Early this morning two dogs killed 69 ducks and left 30 injured before entering the field of sheep and attacking them.
“Do not walk your dogs at the farm – we have had enough.
“These ducks are only three months old and were very difficult to find and replace.
“There will be no more Allarburn Duck Eggs. There will be no more dog walkers welcome.
“We are devastated – this was a prolonged attack on these defenceless animals. The Police are involved.
“Only last week we asked a man to put his two dogs on a lead while at the farm and he refused. He didn’t even have a lead with him.
“We will have zero tolerance and the police will be called in the future.”
Sergeant Michael Irwine said: “Our inquiries into this incident are ongoing and I would urge anyone with information to get in touch.
“Anyone with information should contact police on 101 quoting reference number 2869 of 12 September, or call Crimestoppers anonymously on 0800 555 111.”