It is generally safe for dogs to eat rice, chicken, eggs, and many vegetables as part of their regular diet, but in moderation and as part of a balanced diet. Here are some guidelines:
Rice - Plain white or brown rice is easily digestible for dogs and makes a good addition to their meals. Go easy on flavored/seasoned rice which may contain ingredients dogs can't tolerate.
Chicken - Chicken is a lean protein source full of nutrients. Remove skin and fat. Limit to small amounts or treats, as it is high in protein which can stress kidneys if eaten excessively.
Eggs - Eggs are highly nutritious for dogs in moderation, about 1-2 times per week. Avoid eggs with added salt or fat.
Vegetables - Carrots, green beans, sweet potatoes, squash, broccoli are healthy and low-calorie options. Avoid onions, garlic, mushrooms which can be toxic to dogs.
Frequency - Safe foods like these can be included in meals 1-2 times per day, or every other day if batch-cooking. Too much of one protein source is unnecessary and may imbalance their nutritional needs.
Balanced diet - Make sure their regular daily meals contain a recommended high-quality dog food formulated for their life stage, breed and activity level. Treats and human foods should supplement, not replace the core diet.
In summary, those foods can be included a few times a week as additions to a balanced diet of dog food. Consult your vet if you have any health or dietary concerns for your individual dog. Moderation and variety are key.