I am sorry I made it late to this thread, I would have been among the vast majority that urged you to wait until your first dog was mature and well-trained before getting another puppy. I would like to invite you to consider taking the second puppy back, and explain to the breeder that you are in over your head and didn't realize how much more work two puppies are. You can do this as soon as you feel overwhelmed, but sooner is infinitely better than later.
Seriously--two puppies at once is three times as much work. You have to walk, play with, train, and socialize each pup separately, then you have to be able to walk, play with, train, and socialize both pups together, because each pup will behave VERY differently when its sibling isnt around (I know they aren't littermates, but two puppies this close in age are going to see themselves as sibilings). I have seen it countless times. Two puppies that grow up together consider themselves a unit if they do not spend a significant amount of quality time apart. If separated, they may become extremely distraught, and may have a completely different personality. A pup who is bold may suddenly become fearful. A pup that is friendly may suddenly become aggressive.
Two puppies will have a natural tendency to bond with each other first, and you second. This means that they consider each other far more important than you, and will listen to each other, not you. Totally logical if you think about it--if you were raised in a familly of dogs, and there was one other human about your age, who would you naturally want to bond to? In order to counteract this, you will need to walk, play, train, socialize, and spend quality time with each pup separately. They should not share a kennel, they should not sleep together. They can play together for an hour or so per day, but they should not spend their day together.
Do not be surprised if, even though you train them separately, they do not listen or obey you when they are together. For this reason, you not only have to train each pup separately, you also have to train them together, because they must learn that YOU need to be listened to, no matter if the other sibiling is there or not. So like I said, it is three times as much work.
I am sure that your neighbors have raised two puppies together and said it was no problem--but do the owners care whether the dogs are trained, or well-behaved? What do the owners expect from their dogs?
Since you now have a male and a female close in age, you will need to get them spayed and neutered ASAP. You must not let them have an accidental litter. No excuses. There are different opinions on when it is best to spay/neuter, but in your situation, it would be best to spay your female before her first heat--around 6 months.
Now, even though I wish you'd have listened to our advice, I do hope you stick around, because you're going to need a lot of help and support on raising two puppies together and doing it the RIGHT way. I promise you're going to have questions, and there are people here who have a lot of experience raising puppies the right way--I would take a lot more stock in answers you get here, than the "answers" you get from your next door neighbor, unless your neighbor happens to be a dog behaviorist.
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Luka von Sontausen, CD
Vinca von Sontausen, CGC
Freestep's Beluga Whale, BWD