How old is Pixie ? Usually if it is going to stay erect it will be by 8 or 9 months at the latest. Sometimes as a pup when teething or when they have shots, sleepy, or feeling bad it will flop down. The "leather/Skin" in Roxie's ears are a lot thicker than in Abby's and the ears a lot larger so it took a lot longer for hers to stand up also.The skin just tends to fold in that spot also..... Abby's have been up and stayed up since about 3 months but Roxie's 8 months will still let one flop down at the tip ( the same one) when she is sleepy. But Elena, it doesn't mean that there is anything wrong with Pixie. Sometimes just rubbing that ear upward into postion for a few minutes at a time several times a day when you are petting or cuddling her will help.
Pixie is 1 year and 2 months. Is she still teething? Until 3 months ago her hear they were erect all the time. I thought there was something to do with the food!
Not sure about going into heat, but I know Binks' ears flop every now and then. Floppy ears are nothing to worry about... just gives the little guys character!!!