President Bob Henderson says the society has begun a contraceptive vaccine program on mares in an attempt to lower the wild herd population.
And a new shelter is to be built west of Sundre in the coming weeks to house horses that the society rescues.
Henderson says the group saved nine horses this summer that had strayed onto private property.
In March, Alberta Environment said it counted 880 feral horses in the Rocky Mountain foothills.
A roundup earlier this year upset animal rights activists, but others said the horses compete for grass with cattle and wild animals such as elk.
(CKGY, The Canadian Press)