Mom looks quite young and quite thin too. What kind of milk are you giving them. Cats are lactose intolerant so cows milk is bad but they have no problem with goats milk or a milk replacer which you can find at the pet store. Kitten food would be great for all of them. Momma looks like she needs to gain some weight. I am sure feeding those little rugrats has taken a toll on her. I would say the kittens are around 6-8 weeks. They are a good size.

It is hard to say what the eye thing could be. I might simply be irritated from dust or bushes or anything like that. It could be an infection or any other number of things. When she trusts you enough to hold her (momma cat) then try bathing her eye with some cotton balls covered with warm water a few times a day for a few days. Usually if it is an irritation or a cold in the eye this will help clear it up. If it is more then she will probably need medication to clear it.

They are all really sweet. Hope all goes well with them and that they will get great homes. Good luck.