Some of your criteria are a little contradictory, I think.
If you want a dog that's the most sure to be sweet with your kid, not one to eat birds, and tolerant of your other dogs, your best bet is to look for an adult rescue or retired working/show dog and test him/her out with your pets and family. Dogs often have significant temperament changes between puppyhood and age 2, so a pup or adolescent that's nice with your little dogs and uninterested in your parrots can possibly become predatory, aggressive or intolerant as it grows up, especially if it's from a breed known for sharpness, dog aggression, or prey drive.
If you get an adult dog with a clearly demonstrated agreeable temperament, specific breed isn't as important. "Lab mixes" are ubiquitous in rescue and I bet there's a bunch out there that'd make your kid really happy and would be fine with other animals.
If you get a pup, you can hedge your bets by getting one where the breeder focuses on good temperament and good health, including all the OFA-recommended screenings (a dog that's ill, has impaired senses, or has orthopedic pain can be a snappish dog).
Golden Retrievers and Labs are stereotypical family dogs for good reason. (If you're looking at Golden puppies, make sure you go to a breeder that's working for more longevity and lower incidence of cancer in their breed.) You might also think about a corgi or well-bred collie - they're pretty amiable, but being herding dogs, they're more vigilant and more likely to alert bark, which might appeal to that protective aspect you're looking for. (I feel like if you look for a farm dog type collie and not a show dog type collie, you're more likely to end up with one that's stable, has a brain, and is good with other animals - my parents' collie is from working farm dogs and is safe with chickens, for what it's worth.) Jack Russell terriers are smaller than what you're looking for, but they're sturdy, fun dogs that I can easily see as a companion to a young boy, and they'd be closer in size to your other dogs and therefore less likely to accidentally injure them. Terrier instincts might be a problem with the parrots, though, depending on your setup.
The "guard dog" bit often doesn't play very nicely with the "good with children and tiny dogs" bit. Yes, there are exceptions, but generally speaking, with small children and small dogs, I don't think you want a dog that has a tendency to solve problems with its teeth. Even if the dog is loyal to and nice with its household, if the dog is going to be your kid's dog, a six year old is too young to control a potentially aggressive dog, I think. You want your kid to be able to safely have friends over.
If you want a dog that's the most sure to be sweet with your kid, not one to eat birds, and tolerant of your other dogs, your best bet is to look for an adult rescue or retired working/show dog and test him/her out with your pets and family. Dogs often have significant temperament changes between puppyhood and age 2, so a pup or adolescent that's nice with your little dogs and uninterested in your parrots can possibly become predatory, aggressive or intolerant as it grows up, especially if it's from a breed known for sharpness, dog aggression, or prey drive.
If you get an adult dog with a clearly demonstrated agreeable temperament, specific breed isn't as important. "Lab mixes" are ubiquitous in rescue and I bet there's a bunch out there that'd make your kid really happy and would be fine with other animals.
If you get a pup, you can hedge your bets by getting one where the breeder focuses on good temperament and good health, including all the OFA-recommended screenings (a dog that's ill, has impaired senses, or has orthopedic pain can be a snappish dog).
Golden Retrievers and Labs are stereotypical family dogs for good reason. (If you're looking at Golden puppies, make sure you go to a breeder that's working for more longevity and lower incidence of cancer in their breed.) You might also think about a corgi or well-bred collie - they're pretty amiable, but being herding dogs, they're more vigilant and more likely to alert bark, which might appeal to that protective aspect you're looking for. (I feel like if you look for a farm dog type collie and not a show dog type collie, you're more likely to end up with one that's stable, has a brain, and is good with other animals - my parents' collie is from working farm dogs and is safe with chickens, for what it's worth.) Jack Russell terriers are smaller than what you're looking for, but they're sturdy, fun dogs that I can easily see as a companion to a young boy, and they'd be closer in size to your other dogs and therefore less likely to accidentally injure them. Terrier instincts might be a problem with the parrots, though, depending on your setup.
