*Why does mayonnaise keep chicken moist?
Chicken, breasts in particular, dry out pretty quickly and often need a little help to retain any moisture they can. Mayonnaise is brilliant for a lot of things and this is one of them. The fat and moisture in mayo keep the moisture in the chicken from drying out—it's the baste that evaporates instead. And as an extra perk, the fat in the mayo renders the skin even crispier than usual.