How long do female dogs stay in heat?

I'M TRYING TO MATE MY DOGS. THE GIRL IS IN HEAT. HOW LONG DO THE DOG STAY IN HEAT? HOW LONG DO YOU KEEP THE DOGS TOGETHER AND WHEN CAN YOU TELL IF THE GIRL IS PREGNANT?

female dogs stay in heat for about 3 weeks. a vet can detect if your dog is pregnant within 20-22 days after it occurs, and physical signs start to show around 35-40 days. you should look to see if her nipples enlarge, if her belly looks swollen or larger than usual, she'll probably seem to lose her appetite.

Ok I will answer, but I worry that asking such a basic question and rearing a litter of puppies concern me as to your readiness to be a competent breeder.

She will be ready to be covered around days 11 to 16, when the discharge changes from red to clear. Trying to breed her prior to this time will be unsuccessful and possibly cause her to attack the male.

A good way to check if she is ready is to place your hand flat on her hips, if she swings her tail to the side she is telling you the time is right. Though this behaviour can happen between seasons, so it is worth knowing how she will react off season.

Please read a lot of books, if you can't afford the good books on breeding, you can't afford to rear a litter of puppies. Only breed for the right reasons, I have bred from my kennel a few times, always to keep a puppy for myself. Even with registered litters, I have always but always been out of pocket. There is zero profit and only loss in being a responsible breeder.