Is there a way to tame half-wild kittens?

How old are the kittens? The younger they are, the better your chances of them becoming pettable cats. Some never learn to trust people and they are content to live outside as long as they have food or water. Do not give kittens cows milk. They will have diarrhea. If it is too hot where you live, provide them with shade or a hose mister or even those Blue Ice things where you can freeze them and they will stay cold for a few hours. You need a toy that will help you play with them. One of those feathery things on a long stick works. Don't buy things like balls, etc. You have to be interactive with them. You need to spend as much time with them as you can, even if it is just to sit near them and talk to them. As far as the older cats go, is is IMPERATIVE that you contact a local rescue group to help trap, neuter/spay and return them (called TNR). They will help you. If you do not spay and neuter, you will have hundreds of cats in no time. Where do you live? I hope somewhere when they have a rescue group to help you. Be patient and persistent and get those other cats spayed and neutered as soon as possible. Very important!

Are the kittens old enough to leave their mother? Are you interested in having a cat as a pet? If you are interested in actually have a cat as a pet and the kitten is old enough to leave its mother (which is probably the case if it is able to eat food on its own) then I recommend you try to catch it and bring it inside and spend a lot of time touching it and petting it and getting it to trust you. With kittens, the earlier and the more they are handled the better. If you are not interetsed in having a pet cat and they are going to continue to be outdoor ferals, then you can just continue to feed them and try to entice them into trusting you. With time and patience you may be able to increase your contact with them.

Get them used to the sound of your voice. Talk to them and let them know you care. Just observe them and let them come and investigate you. They are probably already feeling postive about you because you feed them, so just keeping working at it, if you are slow and patient, you may get yourself a nice kitty or two.

Give them time. pet them as much as you can. Let them feel secure in your presence. The more you get to touch and cuddle them more relaxed around you they will be. Some cats are naturally skittish and there is not much you can do about that. Good luck.

Give them time. It took me about a month to get some feral kittens to trust me enough to let me pet them - years later one of them is still here, strictly indoors and he's the sweetest, friendliest cat you've ever seen.