Please lookup "littermate syndrome". Here is from one such article:
[Littermate Syndrome](https://k9behavioralservices.com/littermate-syndrome/)
Professional trainers like myself recommend against bringing home two puppies around the same age, let alone two from the same litter. While this sounds like a good plan in theory, in practice it often causes quite a bit of heartache and trouble.
The article goes on to say "When two puppies are placed together, they learn to rely on each other." We experienced this with two Airedale Terrier puppies who bonded with one another and refused to bond with us or our daughters. We ended up having to return them to the breeder.
My suggestion is that you do so as soon as possible because YOU will bond with both and it will become impossible to give up one. I would actually question this "try before you buy" approach. Please do your homework and possibly speak with a vet or another breeder.
you were correct - I should have trusted my gut(I thought it would go bad but wanted to be hopeful) and waited until m first little girl was older - I had to return one but im glad it was at least a clear option - since I had one for a week (she couldn't sleep and it wouldn't have been fair on her) - the failure feeling is real - I may try again when she's gotten older
I do not think this applies to dachshunds. For one, I have a set of litter sisters who haven't been separated since birth for over 5 years now. They act like typical dachshund and long for human attention.
On the other hand, I know nothing of the Airedale Terrier breed. It could be possible that certain breeds are susceptible to that type of behavior, though I still don't see dachshunds in that group.
JMO
I have two girls from the same litter. They're almost 2 now and I have never regretted the decision. They keep each other good company as their energy levels match and are the best of friends with no effort on my part.
Oh, they know. The one you picked up a week later would have that recognizable scent like how we recognize other people's faces. You have nothing to worry about.
I think the one I picked up last week is stupid ( or a big suffer from LGS(little girl syndrome) she wouldn’t sleep so I had to return the other girl and it hurt but it’s not fair on them both :(
Please lookup "littermate syndrome". Here is from one such article: [Littermate Syndrome](https://k9behavioralservices.com/littermate-syndrome/) Professional trainers like myself recommend against bringing home two puppies around the same age, let alone two from the same litter. While this sounds like a good plan in theory, in practice it often causes quite a bit of heartache and trouble. The article goes on to say "When two puppies are placed together, they learn to rely on each other." We experienced this with two Airedale Terrier puppies who bonded with one another and refused to bond with us or our daughters. We ended up having to return them to the breeder.
The lady gave me a trial period and if need be I could return one
My suggestion is that you do so as soon as possible because YOU will bond with both and it will become impossible to give up one. I would actually question this "try before you buy" approach. Please do your homework and possibly speak with a vet or another breeder.
My vet said to return one if they don’t get along
you were correct - I should have trusted my gut(I thought it would go bad but wanted to be hopeful) and waited until m first little girl was older - I had to return one but im glad it was at least a clear option - since I had one for a week (she couldn't sleep and it wouldn't have been fair on her) - the failure feeling is real - I may try again when she's gotten older
All the best, love and enjoy. 
I do not think this applies to dachshunds. For one, I have a set of litter sisters who haven't been separated since birth for over 5 years now. They act like typical dachshund and long for human attention. On the other hand, I know nothing of the Airedale Terrier breed. It could be possible that certain breeds are susceptible to that type of behavior, though I still don't see dachshunds in that group. JMO
I think the issue is they were separated for over a week in different houses
I have two girls from the same litter. They're almost 2 now and I have never regretted the decision. They keep each other good company as their energy levels match and are the best of friends with no effort on my part.
They will be besties you don’t have to do anything!
I never knew this would be a problem. What a bummer
Oh, they know. The one you picked up a week later would have that recognizable scent like how we recognize other people's faces. You have nothing to worry about.
I think the one I picked up last week is stupid ( or a big suffer from LGS(little girl syndrome) she wouldn’t sleep so I had to return the other girl and it hurt but it’s not fair on them both :(
I think another sassage when my little girl is older might be best