trouble standing

Hi everyone, I have a 2 year old golden (Bella) and a 2 year old choc lab (Charles). The golden is having some difficulty with her hind legs. I am very concerned to see this at such a young age. Yesterday I took the dogs to the park and played fetch for about a half hour. I didn't notice...

Toffee is a healthy 3 1/2 year old pure bred, and has never had any problems. Just this morning we woke up to find her having troubles getting up and then using her hind legs, especially on stairs. She still is interested in food and playing, but can't really do much of either because she's in...