My dog Max has a serious nail problem during the summer season,but we don't know exactly what it is or how to treat it.He is always licking his feet and doesn't let anyone go near them. His nails are somewhat flakey/brittle, some of the longer nails just split in half or twist sideways.Most of his nails are very short, to where they barely stick out from under his fur, however, during the winter months he has no sign of this problem and some of the nails even start to grow.He is an inside dog but he spends alot of time outside is there some kind of vitamin or food we could give him to make them stronger? They have been black colored for awhile but i'm not sure if that's a factor or not. I have tried to research these symptoms but most sites only mention certain breeds,he is a Moutain Feist mix. I would just like to know what is wrong and if there is any home remedies or medicine we could try. Thanks so much