I picked up my pup last Tuesday and everything seemed fine. Yesterday she started with loose stools, we are feeding her Royal Canin Pug which the breeder was feeding her so I don't think the issue is with that. I have however started taking her out in our garden to make. She does her business no problem and doesn't seem stressed at all, although initially she was a little scared as she had not been outdoors prior to this. The stools are not just brown liquid they still have a shape persay but we cannot pick them up in 1 piece. She is eating, drinking and a lively as ever so it doesn't appear to bother her.
It's quite usual for a new puppy to get a bit of an upset stomach initially from the stress caused by the change of home. However, do check with the breeder that you're feeding the right amount of food as under or over feeding can cause this. Don't feed any other treats and don't let her have cows milk. If the loose stools continue or there's any sign of blood in them you'll need to take her to the vet.
I can thoroughly recommend Naturediet which is a complete diet of cooked meat and vegetables sold in vacuum packed trays - easily available from pet stores (or very competitive price from Amazon). Even my recently adopted Romanian rescue puppy who had a really bad stomach on arrival instantly had solid poos after changing her from dried kibble onto this.
Good luck - let us know how you get on and post some photos of your baby soon! :)