This is what definitely helped my GSD ears stand up. His ears went up at 5.5 months and one flopped at 6.5. I waited for three weeks before I researched other solutions. I came across a post about gelatin. Anyway, the ears are mostly cartilage and need collagen to build that cartilage. My boy is big boned with a big head and had Giardia when he was a puppy. I think these were factors affecting his ears.
So what I did. I bought 3 lbs of chicken feet from the Asian market and pressure cooked it about 86 ounces of water in the Instant pot for 75 minutes on high.
hat you will get when the broth cools in the refrigerator is pure gelatin. I gave 100 grams twice a day. The first time I gave it, my GSD's floppy ear immediately stood up the next morning. I was so excited! And then it would flop back after a few hours and I will get frustrated but I soldiered on. Everyday it would stay up longer until I think into the 10th day it stood up for a whole day, but it was still very soft. A trainer pointed it out to me because when my boy gets tired it would start to flop.
It took about three months before I could back off on it and not have the ears go floppy. I still give bone broth because of its health benefits.
I also supplemented with Ester-C, because Vitamin C is important in the formation of collagen.