You can buy devices to place the chicken on but all you really need is a "tall boy" can of your beer of choice ( half full) and the bird will remain stable. What I like to do to prep the chicken before the grill is to first make a compound butter (room temperature butter mixed with different fresh herbs - thyme, parsley, basil rosemary,) and stuff it under the skin and then do a homemade dry rub on top of the skin (oregano, paprika, garlic powder, salt, pepper etc). The bird is then placed on top of the tall boy can and then onto the BBQ using indirect heat.
If anyone is interested in the complete recipe I can post it later.
Go Bills!