Firstly, you need to make sure that your Chihuahua (the mother) is healthy. The problem with Chihuahua breeding is that since they are such a tiny animal either the mother or puppies die during birth unless you are an experienced breeder. Give the mother a little cooked egg, keep her hydrated, and watch her all the time to make sure she is alright.
If the mother is not feeding the puppy, it is because she does not think it will survive. Regardless you should try and have her feed it since the puppy has better chance of survival if the mother is giving it milk.
If the mother refuses to feed it, then don't stress her and take the puppy away. Get some normal milk and start giving the puppy tiny amounts through a syringe (without the needle) or through a makeshift feeder. You will need to feed it every two hours. This will need to be done for four weeks till the puppy can be weaned.
There is no medication I can suggest on the Internet, but I would ask you to not breed your Chihuahua again as next time she could die.
If the mother is not feeding the puppy, it is because she does not think it will survive. Regardless you should try and have her feed it since the puppy has better chance of survival if the mother is giving it milk.
If the mother refuses to feed it, then don't stress her and take the puppy away. Get some normal milk and start giving the puppy tiny amounts through a syringe (without the needle) or through a makeshift feeder. You will need to feed it every two hours. This will need to be done for four weeks till the puppy can be weaned.
There is no medication I can suggest on the Internet, but I would ask you to not breed your Chihuahua again as next time she could die.