Other comments included "ewww", "NEVER AGAIN" or "OMG that is disgusting", while some said they had also had unpleasant meals from the same store.
One commenter shared a photo of their own burger with a hair hanging out of it.
And just two days ago, Jadeo Genet, from Loganholme in Queensland, also posted a photo of a hair in his KFC chicken.
"I, like my family and many other proud Australian men and women have eaten your food for many years," he wrote. "But lately the last trips to KFC we've done have ended in disgusting results. This time a long brown or red hair stuck in the chicken."
Dear KFC Australia
I, like my family and many other proud Australian men and women have eaten your food for many...
Posted by Jade Genet on Saturday, 16 June 2018
He said he would usually avoid saying anything in the hopes it was just an accident. "But enough is enough."
Genet said he was trying to feed a big family with a meal deal "and there's hair all through the chicken", asking whether the teenage staff were wearing hairnets and gloves.
"I'm sorry but like I said this isn't the first time this has happened and it's very disheartening," he added.
KFC Australia replied to the post, writing: "We take these matters very seriously, could you message us directly with the store name, the time of the order and your best contact number so we can have the area manager contact you and sort this out?"
News.com.au has approached KFC for comment.