I believe there were some credible claims of eagles absconding with newborn lambs...and Elmer Keith claimed eagles were hard on Idaho game animals by attacking newborns. Whether they actually flew with them, I don't know.
I sat with a rancher one morning in the Montana badlands and we watched two golden eagles kill a small doe antelope on a flat in front of us. We had been checking fence.
They did not try and carry it away.
Osky