Around 2-3 weeks of age.
The ears open at 14-17 days of age. They should hear clearly by 4 weeks of age. Deafness may not be noticeable while the puppies are together and first noticed when the puppy is in her new home. At about 3 weeks of age, the puppies will begin to imitate the bitch eating and drinking. A secure shallow water dish should now be available at least part of the day. At 3½ weeks of age, the puppies can start receiving puppy mush. Initially a puppy must be about 6-8 weeks old. There is a series of vaccinations pups need re: general health (accounting for breed and weight), before the ones you would gen … erally think of like rabies. It is called heat and they come in to it between 6-12 ms old. It depends on the breed of dog. Small dogs are around 6ms, medium 9 ms and large dogs or X large around 12 ms old … . It last for about 4 week By Dr. T.J. Dunn, Jr., DVM. If your puppy is four weeks old or older, you probably don't have to worry too much about weaning. For the rest of you, follow this basic guideline for weaning puppies from their mothers.  Report Abuse. Puppies will be weaned by 7 weeks old, but shouldn't be re-homed until a minimum of 8 weeks old. Momma dog can be dewormed at any time. The puppies should be dewormed for roundworms and hookworms starting at 2 weeks of age and be repeated at 4, 6, and 8 weeks of age. If YOU bred them, then YOUshould know to the MINUTE how old each pup is! But, that aside, I will answer your question. Dam and litter should be wormed with a roundworm preperation, when the pups are two weeks old, then every two weeks, till twelve weeks. Hearing Changes. Puppies mature quite rapidly after their first two weeks. While their sight and hearing develop, their sense of smell is useful for navigation. Beau will have some rudimentary hearing around 2 or 3 weeks of age, responding to loud noises, but his ears won't have caught up with his sniffer. It will be closer to age 5 or 6 weeks before his hearing is developed enough for him to understand his name. Dog trainer Cesar Millan recommends using positive reinforcement starting between the ages of 5 and 7 weeks of age when Beau responds to his name. Puppies are born deaf and cannot hear until they are about 21 days old. Their eyes are also closed. During this time they rely solely on scent to interpret their world. By the time their sense of hearing is completely developed they can hear about 4 times the distance of a human who has normal hearing.  They CAN be impregnated as young as their first heat cycle, however this is very dangerous for them and unhealthy as they are still a puppy themselves. They SHOULDN'T be bred until after 2 years of age, proper health testing, and being proven in their breed. Physically, yes, a dog can have pups as young as 6 months. But it's not good for them. (It isn't even exactly good for them at the right age.) That said, the earliest age ever should be two years. Mostly because some of the health testing cannot be done until this age. The puppies crawl well by 7-14 days, walk at 16 days, and have a normal gait at 21 days. They need to be on footing that offers traction. By 4 weeks of age, the puppies follow each other and carry toys in their mouths. They will play-fight with each other and learn how to inhibit their bites. At about 3 weeks of age, the puppies will begin to imitate the bitch eating and drinking. A secure shallow water dish should now be available at least part of the day. At 3½ weeks of age, the puppies can start receiving puppy mush. Beau should have fully developed hearing by about 2 months of age. When his hearing has matured, he'll hear things you can't. Dogs can hear in the frequency range of approximately 67 Hz to 45,000 Hz, compared with humans' range of 20 Hz to 20,000 Hz. They can hear across greater distances -- about four times the distance you can hear. It will be closer to age 5 or 6 weeks before his hearing is developed enough for him to understand his name. Dog trainer Cesar Millan recommends using positive reinforcement starting between the ages of 5 and 7 weeks of age when Beau responds to his name.
http://www.peteducation.com/article.cfm?c=2+2108&aid=916 http://www.answers.com/Q/When_can_puppies_first_hear http://www.petmd.com/dog/puppycenter/nutrition/evr_dg_weaning_puppies_from_their_mother https://answers.yahoo.com/question/index?qid=20071028115308AAremJb http://pets.thenest.com/newborn-puppies-start-hearing-12168.html http://www.dogbreedinfo.com/articles/dogsenses.htm http://www.dogster.com/answers/question/how_young_can_a_dog_or_puppy_have_babies-28581 http://www.peteducation.com/article.cfm?c=2+2108&aid=916 http://pets.thenest.com/newborn-puppies-start-hearing-12168.html
how old do puppies have to be before they can hear