You could take pictures of all the babies. Then open the photo files in Microsoft Paint, Adobe Photoshop, or any other photo editing program that has a text feature. Write any important info on the photo in one of the corners. Print the pics, sign the backs, and your done.
Or you can use MS Word or Powerpoint to add multiple photos, including parents and the baby. Then add the info somewhere on the sheet and print it up on regular paper. Or better yet print them on resume or cardstock for a little better quality paperwork.
When adding any information remember that paperwork serves two functions. One, it serves to provide a little reassurance to the buyer that the animal is what you say it is. Two, if someone shows up in a few years saying that their animal is not a het, you can look at the original paperwork and compare the picture of the animal to the adult. Using pattern mapping you can make sure that they have the right animal to go with the paperwork. Without the paperwork someone could just switch a normal for their het and you couldn't tell the difference.