Originally Answered: pros and cons of seed and pellet diets for parakeets?
1) If the only healthy diet for a pet is what it eats in the wild, then we should be feeding our dogs and cats whole small animals, too. After all, "pelleted" dog and cat diets aren't found in the wild, either.
2) Parrots don't eat much seed in the wild, in fact, and certainly not the types of seeds one finds in commercial parrot mix. They eat a wide variety of foods that you can't hope to duplicate unless you start importing them from South America. Parrots in the wild eat plants, tubers, fruits, grains, nuts, flowers, seed, insects, and sometimes carrion.
3) Seed diets are deficient in vitamins, minerals, and amino acids. In the wild parrots can compensate for deficiencies by eating other things. In captivity, they are dependent on what you give them, and if that's mostly seed they have no way to make up for what the seeds lack. In particular, an all-seed diet lacks calcium, which is very important to parrots for maintaining their delicate bones. Seeds also are lacking in complete proteins, which birds need in order to replace and grow feathers, which are something like 98% protein.
4) The premise that "birds eat seed" comes from watching small seed-eating softbills. We don't have any parrots native to the U.S. (although the QP's seem to be working on it ), so we don't have first-hand observations about what they eat. (And many of these seed-eaters also eat insects for protein. Remember "the early bird gets the worm?") You can't determine what parrots should eat by watching starlings and sparrows!
5) A healthy diet for an olympic athlete would be a good healthy diet for you also - right? The comparison is valid. Wild Quakers (and other parrots) fly miles daily in search of food and need a high-energy diet. Our "perch potatoes" will tend to be overweight and have associated health problems if fed the same type of high-fat diet that they eat in the wild. This is especially true of Quakers, who are prone to obesity and Fatty Liver Disease in captivity. Research has determined that a parrot's diet should be about 12 - 15% fat. Most seed mixes are much higher in fat than that, and it gets worse by the time they have picked out and eaten their high-fat favorites, the sunflower and safflower seeds.
6) Based on my personal observations as a vet tech, the reading and research I have done, and my personal experience as a breeder, I will say that parrots on pellets and a varied diet of vegetables, fruits, grains, and table food live longer, are healthier, have better color and feather condition, and are more active and playful.
7) Parrots have taste buds and in some ways are like small children - they will eat the most of what they like the best, which isn't going to be what's good for them. Although a high-quality, supplemented seed mix -may- actually be a fairly well-balanced diet if eaten in its entirety, it won't be after your little darling has finished picking out the parts it likes the best and dumping the rest on the floor.
Your parrot's diet should consist of a pellet BASE ( 60 - 70% pellets), vegetables, grains, legumes, fruits, other table foods (20 - 30%), and some seed. The greater the variety of foods you offer your parrot, the more likely it is that it will be able to meet its nutritional needs.
—–More About Seeds and Seed-bearing Treats—–
Seeds are a natural, high-energy food that are good nutrition as a -limited- part of a balanced diet (I sound like a cereal commercial!). Seeds are not inherently bad, they are just incomplete, and some are high in fat. When used in combination with other things that make up for what they lack - sort of like putting red beans and rice together to get a complete protein - they can be a useful addition to the parrot's diet.
The "small" seeds, such as millet and canary grass seed, are high in carbohydrates, relatively low in fat, and a good energy source. I think you'll find that most of the seed content in Nutriberries and Avicakes is this type of seed rather than the high-fat sunflower and safflower seeds. The treats then have pellets and other things such as grains and dried fruits added and are coated with a sticky coating, sort of like honey, that dries hard and holds the treat together and contains nutrient additives. Because of the nature of the coating, the parrot almost has to ingest it while eating the treat, which is not true of the methods used to add supplements to loose seed mixes.
Because of the coating and the way the parts of the treat are "glued" together to make it difficult for the parrot to eat only the parts it likes, these treats do overcome some of the problems associated with loose seed mixes. While I personally wouldn't feed them as a main diet, they probably come far closer to being a complete diet than a conventional seed mix.
The problem that arises with seed is when people try to feed a seed mix all by itself, as the whole or great majority of the diet. It's not so bad for the small