My 14-mo beagle has started to stand in three legs when she is standing, she will not put her full weight in her right hind leg. She walks and runs ok and still jumps in my lap. I just came back from a one week vacation, she stayed with my father and he said that during that time she did not get injured. I checked her paw to see if she had something but everything looked ok. She does not cry when I touch or examine her leg. Could it be a strain? I'm puzzled.
One of our dogs did that too and I took him to the vet and he had a problem with his nails. Freaked me out! Anyway, His nails are very brittle and they break very easily, (plus he runs hard around the pool) so he had to do a nail coterization. The dog is put under for this, and it is painful, but he has not had any problems since. I wish you luck.