I'm not sure what behavior is "normal" when training the retrieve since I just started myself. I know that Judy Alder suggests teaching the commands in the following order: "take", "hold", "give", so that's what I've been doing. We've got "take" down, so now I'm working on "hold". I give the "take" command, and while the bumper is in her mouth, I tell her "hold" and gently hold her mouth closed, wait 2 seconds, then let her open her mouth. And of course, tell her good, and give a treat.
She hates it, hates it, hates it, but she hated the "take" command at first too.
I also read that if you teach them the "take" command with one item such as a ball or favorite toy, that when you give them a bumper and say "take" they act like they have never heard the word "take" before, although it will go much quicker then when you first started with the "take" command.
I'm hoping Judy's book is ready soon, cuz I could really use the help !!