How to make young kittens poop?

Ok so here's the scoop. I live on a farm and before i moved here my aunt lived here and had a kitten that ended up being pretty wild and now as an adult cat wil not come near humans. Well my Hubby went into the shed to see if there was any extra room for storage. He found 4 kittens were guessing about 4 weeks old. Just judging by their size, how many teeth they have, and their ability to walk etc. The only problem is we cannot handle any more wild cats around here as we have 2 cats of our own that are already getting attacked by the wild cats. So we took them in. Also this mother cat has had MULTIPLE litters alot of which we never found until they were dead, from it being winter. We brought them in about mid day yesterday. They have eaten about 6 times but still have not pooped. I know that your suppose to rub their genitals with a warm wet paper towel for stimulation like the mother would with her tongue. Iv tried this before and after each feed. Iv only been able to get all of them to pee once, but no poop. For their food iv been giving them "catmilk" from a medicine dropper, they have started a little to drink out of the dish on their own but are still having a little trouble with it. We are using special wipes for their eyes because they have quite a bit of brown crust around them. Also one of the kittens had a very dark yellow pee compared too the rest and at the end of her peeing a little brown came out with the pee, was not poo i watched... So why could there have been brown in the one kittens pee? And how can i get them to poop? We are going to get some de-worming stuff tomorrow, are they too young for it? ANY additional advice appreciated!! Thank you