Carrots and feed it some fruit. DO NOT feed them straw it will kill them and everyday give them hay. hay should be unlimited. Apples, bananas, pears, never feed them lettuce or cabbage. no tomatoes, never any seeds ,no sugar or anything and only give water to drink. I know from experience, I have 5 bunnies and they are all happy and healthy clean cages every other day, water unlimited.
You can try giving your pet dogs green leafy vegies. And aside from vegetables you can also give your dog a natural food supplement like Apipet Gastro (It is a 100% natural supplement for dogs APIPET GASTRO contains a unique combination of bee products with ginger. Bee formula contains propolis and bee pollen of the Dalmatian plant Businac.) and Apipet Immuno (It is a 100% natural supplement for dogs APIPET IMMUNO is invented with the unique recipe of bee propolis and bee pollen dominated by the pollen from Dalmatian plant Businac (Cistus sp.)