We collected our pug puppy at the weekend and we changed her food as the breeder was feeding her adult food. It is the same brand though.
Her stools are loose and sometimes runny. Otherwise she seems to be a happy puppy, active, eating well etc. She is due for a checkup at the vets Monday but any advice in the mean time? Should I have changed her food gradually 
Hello Pugmomma and welcome to the forum. It is a very exciting time with a new puppy. I may have been inclined to wait for your puppy to settle into your home and then change her food gradually if it were me. You don’t say which food you are feeding her but if say you are feeding a raw food diet there is no or little difference whether it is the puppy or adult food. I cannot say about kibble as I haven’t fed kibble to my dogs. I feed Coldpressed Gentle food in the morning and raw in the evening which is suiting my girls but mine are in their senior years.
Hi Lottie, thank you for the reply. She’s on Butchers puppy perfect (I’m in the uk) which is rated 90% she’s been on it now for 3 days. She’s 11 weeks and has also been wormed and had flea treatment up to date.
Hello and welcome to the forum Pugmomma. Puppy food usually has a higher fat and protein content to help with their rapid growth. Some adult foods have high protein content too so can be used for pups. However, if it was not one of these then I would hazard a guess that the the difference in nutrition between that and your current food has been too great for the pup’s digestion to deal with. Butchers Puppy Perfect has high fat - 33.3% and high protein - 44.4%. The carbohydrate content is low.
Overfeeding can also cause these symptoms so make sure that you are giving the correct amount. Often the RDA as stated on the packaging is higher than the dog actually needs.
Puppies are best left on the food that the breeder used for a while until they are settled. Transition to a new product should then be gradual. Talk to the vet and perhaps look at finding a good food that will suit your puppy. If it doesn’t improve ask for a stool analysis to rule out infection.
Thank you for your advice, I reduced her food amount as I thought what we were giving was too much, it has made a big difference already! I’ll speak to the vet also on Monday. Thank you again