Pigeons have a largely low or non-fibre diet.Grains should be fed the most. Dried field peas make an excellent staple food, Corn is an excellent winter feed as it is readily stored in the pigeon's body as fat, but it shouldnt be overfed. They also eat sorghum & barley.
I fed a mixture of 30% peas, 30% corn, 30% sorghum and 10% hard wheat. Alot of feedstores carry pigeon mix.
Theres also pigeon pellet,but I dont like thosey have alot of meat by-products in them.
They need grit, The best grit is hard granite or quartz.Pigeons also like salt and will readily attack salt blocks such as those made for horses and sheep.