I would highly recommend a retriever actually for that exact reason - even though they are quite likely to put things in their mouth, they are naturally quite gentle. We used rolled up socks as trainers - they're soft and you can fill them with feathers or interesting smells so they get used to carrying interesting smells without chewing. We had a game where every morning dad would be getting ready for work and it was the puppy's "job" to go to the laundry pile and "collect" a pair of socks and take them to dad.
Over the years our dogs have retrieved "everything!" - baby rabbits, baby birds, even frogs! You come in and find them nestled on their blanket licking and "mothering" their find LOL.