How to tell if my mother dog is still producing milk for pups?

Suckling dormant mammary glands stimulates hormone production and can make them produce milk again, especially if the female has had puppies before. In the wild dogs share the care of puppies. In a pack usually only the alpha female has puppies, but all females involved in the care of the puppies will lactate and feed them. So, yes there is a possibility that the empty bitch is lactating and feeding the puppies even though she herself does not have puppies.

If she stopped feeding them suddenly then mastitis would be a risk (she may refuse them because it is painful or the excess milk after she stopped could cause the problem after). If she is off form, has any fever or her milk glands are red, hot or painful to firm touch then she will need prescription treatment from a vet. If everything is otherwise good, just monitor for any changes. 48 hours of very light food if she is healthy and not underweight can discourage active milk production but do not starve her

If she had puppy recently and she was feeding them, is normal to produce milk for few days after stopping the activity. Without puppies stimulating milk production by suckling, Gracie will stop the milk production soon. Do not squeeze the milk out otherwise she will continue to produce it and monitor the mammary gland. If the glands become painful/red/inflammed, please seek veterinarian attention. Please post again on the forum if you would like to discuss it further. I hope my answer was helpful.

Weigh the puppies daily. They should be gaining weigh every day, and if they are not, then they are not getting enough milk and Heaven's milk may be drying up. In that case, you will need to bottle feed the puppies with puppy formula.

If Maple is not the mother, then she won’t have the proper hormones to get milk. The only way you can tell if the puppies are getting enough milk from their mother is to weigh them daily in a gram scale to make sure they are gaining weight every day.

If the puppies are latching and nursing then stop to sleep with firm tummies they are more than likely getting all the milk they need. If they seem distant or cold to the touch and not trying to Nurse you can always bottle feed one to measure the amount they are getting.

She may be having a false pregnancy. If she had contact with a male while she was in heat, she could be pregnant. She could also have a hormonal problem or a mammary tumor. It would be best to take her to a veterinarian for an exam. The vet can also tell you whether she is pregnant. Unfortunately this is impossible without a hands-on exam.