First of all, there’s no reason to have a dog chained up if the backyard is secure (by secure I mean that the fence goes all the way around the property and not short enough for the dog to jump over).
Secondly, it depends. If it’s really cold or really hot, the shelter you have may be inadequate for the conditions.
If the dog is injured or has signs of having been in a fight, they can take it.
Why? Is the SPCA trying to take your dog?