2 Answers

Causes
Medical conditions such as hypothyroidism or hyperthyroidism, malnutrition, vitamin deficiencies and skin conditions, including psoriasis, may contribute to brittle, flaking nails, according to MedlinePlus. Exposing your nails frequently to water, usually through hand washing, can also cause brittle, flaking nails. Other causes include exposing your nails to chemicals including cleaning chemicals, nail polish and nail polish remover.

Treatment
Apply a lanolin-enriched lotion or one containing alpha-hydroxy acids to brittle, flaking nails after bathing. Natural treatments for brittle, flaking nails include vitamin supplements of calcium, biotin, iron, silicon, vitamin A and zinc, according to the American Osteopathic College of Dermatology.

Preventing
Wear cotton-lined rubber gloves when washing dishing or performing other household chores which involve water, and keep your hands out of water as often as possible. Dry your hands thoroughly when you must wash them and always apply a lotion to hands and nails after they are exposed to water. Wear gloves in winter and avoid using acrylic, porcelain or glue-on nails. Some nails polishes may protect the nail bed. Use a brand that adds nylon fibers to provide extra strength to nails, according to University of Mississippi's health care site.

Warning
Contact a medical professional for treatment or to test for underlying medical conditions if you notice blue nails, white lines, pale nails, clubbed nails, horizontal ridges or clubbed nails. Do not pick or tear at the brittle, flaking nail.

Read more: http://www.livestrong.com/article/310417-brittle-flaking-nails/#ixzz2QgV4q9bx

Try applying "Hoof Flex" intended for horses, you can get it from an animal supplier or a grain store.  I think you will be pleased.