Size B is used for pheasants from 3 to 6 weeks or quail and partridge 3 weeks and older. Can also be used on chickens.
Size C is used for pheasants from 6 weeks on but not to be used for breeding cocks. Bits are to be used primarily on birds that will be released at 12 to 14 weeks of age. When using size C, for a few days prior to applying the bits, give the birds pelleted food in deep containers. MASH SHOULD NOT BE FED!
Plastic has a few advantages over metal: they are easily applied and removed without a tool; the can be reused; they do not cut into beak as metal bits do; and it is easy to change sizes as birds mature.