Wolmarans is calling for anyone with information to pass it on to the police or SPCA.
In a Facebook post this morning, she said the shelter needs help to move animals to safety in case there are further attacks. They will not be taking any new animals until the situation is more stable.
Originally from South Africa, Wolmarans started Pixies in 2012 in memory of her daughter who was killed in a road accident at the age of 18.
The animal rescue cares for nearly 400 animals every year.
"We pray for the safe passing over the rainbow bridge of the 11 animals that were brutally slaughtered and we pray that their suffering during the attack was short," Wolmarans said in her post.