For the most part you really shouldn't have to clip beaks. The only reason you would have to do this is if the chicken has a slight over bite, or has some other deformity of the beak. Occasionally I will get a bird that has a beak where the top will just grow longer than the bottom. It will curve over and can affect how they eat. This is an easy fix should it happen. Every few month you can just take a nail clipper (I used the kind for dogs with the hole at the end) and snip off the little over hang.
As far as nails go, you shouldn't have to cut them either if they free range or live on the ground in a coop. However, you may have a chicken that has a funky toe that may need to be clipped. Eventually, long nails that go unclipped will grow into a loop and can actually go through the skin of the toe itself, causing lots of other issues. Also, chickens and other poultry raised on wire floors will need their nails clipped regularly. Many people will also clips nails right before a show. If you do need to clip nails, just be sure to take off the tips. Try to avoid cutting too far on the nail, otherwise you will hit the quick and cause the bird to bleed. It's not that big a deal, but can be painful for the bird. On hot days it can be difficult to get the nail to stop bleeding. It's usually wise to have a bottle of styptic powder (flour can be used as a substitute) on hand when cutting nails just in case.
