duck attacked by dog wont use one leg

[Puranin]

She has no cuts or scrapes just missing some feathers and I'm pretty sure she injured her toe but she seems to use it ok just her nail wont straighten and was grindy at the joint. more concerning is that she wont put her leg up under her. She leaves it straight out behind. she swims and uses from the knee down fine, but can only hobble a step or two before falling and leaving leg out behind. any ideas on how to test for hip injury or treatments?