Brittle Nails

So Zoe doesn't have overly long nails and she's broken 3 now since she's been with us. I think she's just has brittle nails. Does anyone have any suggestions as to a supplement that I could add to her food to help her grow more healthy stronger nails?? I have her on Canidae food and it's a much better food than the rescue had her on and I think it's helping but I'd like to add a little something extra to help get those nails strong and thick like Angel and Tweeder's nails.

Are her nails a good length. If they are too long, they can break.

How about fish oil capsule ??

Her nails arn't too long. They're not encredibly short either. However they are considerably slender and more brittle than Angel and Tweeder. I'll have to try either the folic acid or the fish oil capsules in her food to see if that helps. Thanks for all the suggestions!!!