Both the Cardigan Welsh and Pembroke Welsh corgi are known for their fox-like appearance and large, upright ears. Young corgi pups don't have upright ears, they have drop ears. As they grow and develop, the ears begin to rise, starting at around eight weeks of age, although the ears of some pups will remain flat.
What Big Ears You Have!
Corgi pups aren't born with upright ears, but rather with drop ears that lie flat. As they mature, usually starting around eight weeks of age, the ears may slowly begin to rise. Your pup may even have one upright ear and one drop ear as he develops, making him appear a little lopsided. Soon enough, though, usually by the time he reaches between four and six months old, both of his ears should be upright. Sometimes the ears on your pup will droop while he teethes, but become upright again after this process. Note that some pups will never develop upright ears and they may remain drop ears for their entire lives.
The Ears Have It
Upright ears are part of the American Kennel Club breed standard for corgis, so if your pooch doesn't develop them, you may not be able to show him, but that doesn't mean that he won't be a great house pet. Some breeders recommend taping the ears of a puppy to encourage them to develop upright. Consult with your vet to determine if ear-taping is appropriate for your pup.