With coyote the females don't show they have nursed pups after they have weened them for a month and a half. If they did then the females fur wouldn't have any value to it even in good years, like a milk belly bobcat. They will still have small lumps on their uterus till August or September, however. When the pups get to be as large as an adult ours have thin ears till after they go through a cold winter, their teeth will be a little smaller than an older adult and be sharper with good points on the canine teeth, the molars will be sharper and clean with no tarter build up on them. I got in the habit of opening the females up so I could check to see how many if any pups she had given birth to by counting the lumps on the uterus, you can after a while figure pretty close to how long ago she whelped also by the size of the lumps, and figure how many pups I was looking for, but I was doing it for control and needed to get the pups as well as the adults. Ageing a coyote is a little different then ageing a domestic dog but not a lot, it takes a little practice and helps to have people that can help you learn how to. I would think a Veterinarian would be able to give you a quick lesson in ageing your dog and you could relate it to coyote, At one time I had a pup chart that would tell me how long the female had been carrying the pups and when she would have given birth and kept records of this information, I gave it to the biologist at the USDA Wildlife Services office when I quit working with him. I will still be interested in the life cycle of the predators till I die they have and will continue to fascinate me all of my life. You all be careful coyote hunting and control can become an addiction; I have no hatred of the coyote I have a deep respect for their ability to survive and the fact that they will both the female and male do what it takes to keep their pups alive, if you kill one of the adults but not both of them, they will often bring another adult in to help them raise the pups, if you kill both the adults and the pups are at least a few weeks old another coyote or pair will adopt them. Some of the things that I have seen, and experienced coyote do a lot of people wouldn't believe without being there to witness it for themselves. Breeding season is just around the corner for the coyote and the little red fox will be starting to cycle within a couple of weeks as I have found a wet female fox as early as March 3rd, she had the kits just a couple of days earlier they were still dark brown and had their eyes closed so if you count back 62 days that would tell you when she was in season.