It is not uncommon for halflings to be vegan/vegetarian, and grass-types may be solely carnivores (being plants themselves, they might not want to eat any plants). Some people may omit only eating their related Pokemon. Some might eat their 'spirit animal' on purpose, to "gain it's knowledge and power". And then there are still commonly halflings that care not what they eat, because in the end, everyone needs to survive. All of this comes down to personal preference, and while there are small arguments over what to eat and what not to eat, there have not been any wars incited because of the food issue.
These animals are the most commonly eaten:
Birds:
Psyduck
Golduck
Farfetch'd
Delibird
Torchic
Combusken
Swablu
Piplup
Starly
Pidove
Tranquill
Ducklett
Swanna
Fletchinder
Hawlucha
Reptiles:
Squirtle
Totodile
Torkoal
Turtwig
Sandile
Tirtouga
Fish and Sea Creatures:
Shellder
Krabby
Kingler
Magikarp
Omanyte
Remoraid
Octillery
Mantine
Sharpedo
Barboach
Whiscash
Corphish
Feebas
Clamperl
Finneon
Lumineon
Mantyke
Basculin
Eelektrik
Stunfisk
Clauncher
Frogs:
Poliwag
Poliwhirl
Politoed
Croagunk
Tympole
Palpitoad
Froakie
Rodents:
Pikachu
Raichu
Plusle
Minun
Bidoof
Bibarel
Pachirisu
Buneary
Patrat
Minccino
Cinccino
Mienfoo
Dedenne
Pigs:
Swinub
Piloswine
Spoink
Grumpig
Tepig
Pignite
Venison, Goats, and Sheep:
Mareep
Flaaffy
Stantler
Whimsicott
Deerling
Sawsbuck
Skiddo
Gogoat
Bovines:
Tauros
Miltank
Bouffalant
