How long does it take for 2 chihuahuas to have puppies?

Thank you for rescuing pregnant mixed breed dogs. There are lots of questions from disreputable breeders on here about pregnancy, so you might want to look into those or contact the rescue group where you rescued the dogs from. Thank you for not contributing to the 2-5 million unwanted animals killed each year in shelters.

I assume you rescued because a ehtical breeder would never breed mutt dogs and would know about pregnancy.

Once they have given birth, and hopefully they will survive, please have them spayed ASAP.

Good luck to you!
References :

its considerd best to breed after 2 years but it is ok to breed after 1.
estation is about 63 days
whelping (giving birth) time depends on the female and the amount of pups also if there are any birthing problems.
but NEVER leave more than 2 hours between pups being born with out calling the vet.

it is also best to inform you vet that they are due soon and tell them when they start, that way if any problems occure you have the vet on standby.

good luck
References :
3 years animal care courses

Well lets see dogs can come into heat any time after 6 months of age. But normaly it is best to wait. In any case your dogs are old enough to have pups.

Well before they go into labor there temp will go down to around 98. That means you will have pups in 12 to 24 hours. Well you dog goes into labor it can be sevarl hours or it can be a few. Every dog is diffent I recomend a good book or a movie! A good way to help speed it up safly and help the mom is after that first puppy let it start to nurse off of momma. When a another puppy is comming and mom start moving alot just put the puppy aside untill the next puppy has come that way you keep the fist puppy safe. When they nurse off of momma they relese Oxitostion (spelling ?) in a very smal amount. It is also very good for the puppy too. That way is gets momma first milk!
References :
Breeder and Groomer