3 day old kitten wont stop crying.?

one of our cats is a young mom shes jsut on a year old and has had her very first litter. everything is going well seames like she is feeding them enough but one of them is always crying. even when its feeding. the mother keeps moving it to be on its own and feeding it there but it will still keep on crying.

back ground on the mom:
she has separation issues cant spend more then an hour without seeing me,, she can become really frantic to get to where i am. we have been able to lessen it by having soft toys near her. 

this is her first litter and isn't dealing with it to well by the looks on her face. there is four of them so im guessing this is far to much for her.
any help would be great

Answer

James:
Unless you are a professional breeder, there is no reason for your lady to have any more kittens, and it seems to stress her out to have them. I would recommend having her properly neutered as soon as the vet thinks it is advisable, and please -- keep her away from males until that is accomplished, no matter the inconvenience or whatever it takes. We just do not need any more kittens, you know. As it is, you would be aghast at the number of kittens put to death in shelters continually.

I would strongly suggest that you keep a very close eye on the kitten who is crying a lot. If it is not getting sufficient nutrition, your vet can advise you on the amount of supplement to give, etc. That kitten's crying for a reason if it is the only one, and Mom isolating it suggests she may think it is the runt, which may mean it may be at risk of starvation.

I would say you have a lot on your plate with this group.

Mamma Cat:
Obviously, the mom is rejecting the kitten and it is hungry. You need to step in and start feeding it KMR and still putting it up to a moms teat to eat. 

I foster many kittens. Some with mom, some not. But, when a kitten is crying, it is cold and hungry. I will bottle/dropper feed the crying kitten every (I don't know the age of the kitten, but birth to one week, every 2 hours, one week every 3 hours, age 2 weeks, every four hours. 

Mom may be stressed. You can provide a flealway defuser to calm her, but you need to get the kitten back with mom. 

Vicky:
Dont worry we will not be breeding her or her sister. one litter is enough.
we moved her to a area closer to me, thats a lot darker and she has calmed down a lot. so has the crying kitten if it starts up again we will be hand feeding it.