Some corgis are slow about putting their ears up and some drop their ears after having them up.  There are several reasons for this, teething, weight gain, growth spurts, stress, to name a few. However,  although their ears may go up and down periodically until they mature,  they will eventually come up and stay up.  It could take until the puppy is one year old for it's ears to stand permanently.  You should be aware, that the corgi is a big dog in a smaller package.  The emphasis on smallER, an adult male will weigh 30 pounds and a female about 25.  They are not a toy breed and need alot of exercise.  They are very friendly and should never be snippy, however they do have a mind of their own and need training to keep from becoming pushy.  They are herders and their natural instinct will take over occasionally and they will herd anything at hand, another pet, you or your children.  Their coat, although not long, does require quite a bit of grooming.  Weekly brushing to remove the dead hair is recommended.  They do shed and once or twice a year will "blow" their coat.  Meaning the entire under coat will come off at once.  During this time, more brushing is required and the undercoat will come off in large handfulls.   Keeping them inside in a controlled temperature year round does help with this process. The corgi is a generally very healthy breed, they can experience back problems, PRA and glaucoma.  They also have weight issues.  The Corgi is very prone to becoming overweight and their food should be measured carefully, exercise is also very helpful.  I haven't seen any of these problems in my bloodlines and I do try to screen very carefully to avoid any such problems.  Above all, the Corgi is a friendly affectionate dog that has a lot of love to give.