60 to approximately 70 foals are born into the Chincoteague herd each year. The annual Pony Pennings are used to maintain the herd size at around 150 animals. Since 1943, the FWS has been working on the island to protect and increase the wildfowl population, and their efforts have sometimes endangered the Chincoteague herd. Due to the placement of fences by the FWS, a reduced amount of land is available for grazing by the ponies. The fencing also prevents them from reaching the sea, where they often went to escape biting insects, including mosquitos. In 1962, several ponies were trapped in an enclosure by high water and died when they were carried out to sea during a storm. Unlike the Maryland herd, ponies on the Virginia side of the island are fenced off from roadways to prevent auto accidents and to discourage visitors from feeding the ponies.