When they are 5 weeks old they just look like little adults. Most shops accept hamsters at 6 weeks, so if they are closer to 5 weeks they should look, albeit small, almost at selling age. 3-4 weeks of age, they are small, a little wobbily, and have large heads and very round tummies. If they are 4-5 weeks old as you suspect, they should almost fill your palm and be steady and sure on their feet. Hope that helps,it's not a very good description I know. I thought I had some pics but I don't. :/
I would advice just to keep handling them, regularly but very gently. I would hold them over a surface or very low to the ground, as they are very likely to suddenly jump, and at that age they are very fragile. It's a good idea to start by gently cupping them in your hands, and letting them jump off if they want to, so they don't see being handled as a potential threat. Baby hammies are quick learners, and it won't take them long to get used to the idea. Allow them to eat a treat off of your hand, but also handle them without treats so they don't just associate your hand with food.
As for how much they eat, it depends on the age. If they are indeed 4 to 5 weeks old, they should be eating solids (dry complete mix), but preferably broken into smaller pieces. A small teaspoon of this a day should suffice, but it's a good idea to supplement their diet by offering a small serving of milky porridge/oatmeal in a shallow dish, or a piece of high quality dog kibble, either solid to encourage them to gnaw, or if you think they might be younger, soak in a little warm water or milk. Be aware though that milk sours quickly, so if offering milk in the form of porridge or used to soak solids, if after a couple hours they haven't eaten it or have left excess, remove it. A small piece of hardboiled or scramble egg is a good idea for a rich source of protein, but should only be offered sparingly. You could also give a couple of mealworms, live or dried.
Hope this offers some help!
