How old should they be before going to new homes. I have just started feeding them food. What do I have to do to wean them or does the mother chihuahua take care of that?
I wait until the puppies are 12 weeks old before they leave home. This allows them to get plenty of time to learn about bite inhibition and about living in a family (learning about household sounds and activities). Puppies also go through a fear period around 8-10 weeks old so this allows them to learn in the environment they feel safe in.
As for weaning, starting RIGHT now, grind puppy food with water to make a paste. Take each puppy an a put some of the paste in their mouth. Do this everyday for about a week and increase the amount you are feeding them until you are giving them all the food they need without momma's milk. Momma can be taken away to dry up after they are eating on their own and drinking some water. Once Momma is dried up, you can give her access to the puppies again. I do this for the momma's health. The nursing is actually more stressful on the momma than the pregnancy. I also have other chihuahuas in the house (including the dad) and they help and play with the puppies too.
In a short time you'll be able to reduce the amount of water until they are eating dry kibble and drinking fresh water.