Police in Lancaster County told the (Lancaster) Intelligencer Journal/Lancaster New Era that the boy was playing with other children in a New Holland pasture on Thursday morning.
Lt. Jonathan Heisse said the boy approached a pony from behind and the animal became startled and kicked him in the throat, causing him to be unable to breathe.
Emergency responders from New Holland Ambulance and Ephrata Community Hospital were called and the boy was airlifted to Hershey Medical Center, where Heisse said he died Friday.
Heisse declined to release the name of the child but said he lives "outside the area."
Information from: Intelligencer Journal/Lancaster New Era