I don't know Billy or his parents, so it's hard to know the exact reasons. However, here are a few possible reasons:
Dogs can be expensive to own: There's food, there are vet bills, licensing, dog toys, dog bed, training classes, and so on.
Dogs shed their fur. That means that their hair and dander get all over everything, and someone has to keep things clean. Also, if someone in the house has Allergies, a dog could possibly make the allergies worse.
If there are specific breeds of dogs that Billy wants, they might be very expensive. Also, it takes time and research and education to be sure that the puppy isn't being bought from a puppy mill.
If Billy wants a big dog, maybe the parents don't want a big dog around.
Dogs take a lot of care and responsibility. They need to get good exercise, running, every day, at least a couple of times a day. They need to be groomed, fed, trained a lot during their first year or two, have fresh, clean water at all times. Many kids say that they'll take care of all of that, but also many kids do it for about a week and then don't do it any more, so the parents have to do it.
Billy could ask his parents why they won't buy him the dog he wants. If it's because they don't want to have to take care of it, maybe Billy could prove that he's responsible by taking on a couple of new household chores and doing them every day for two months without complaining or missing even once, and see whether that could convince his parents that he would always take care of the dog. No guarantees, though.
they can't afford it
He'll just have to keep living with his parents.
my dogs are interlocked and they wont release
It's not worth it.
they wont hunt with any other person but them and old dan wont hunt without little and - love ya peps that r cheating ;3
Dogs wont get a cold sore from people.
yes you can some dogs may like it but some dogs maybe wont
By decreasing human wants if human wants get limited people wont have to mine
you wont notice when she does because dogs go into heat and do not bleed.
their is millions. but soon their wont be if people keep killing and slaving them. SAVE THE DOGS!
it depends on what type of food theres somefood that dogs wont touch
you can but some dogs wont like it