Answer
Collie:
Depends on the crate and depends on the dog.
At MANY dog shows, people will cover their over stimulated dog's crate until it's their turn. Covering helps the dog settle down and relax until it's time to focus. Opposed to wearing themselves out by barking at everything that walks past.
Adversely, some dogs dislike being covered. And some will even pull items such as a blanket into their crate and destroy them.
So really, it's whatever works best for your dog.
Jojo:
Covering 3 sides and the top can make the crate into a private den for a dog to feel relaxed in.
(A dog should not be shut in a crate more than a few hours at a time and possibly at night and when owner is out if the dog is destructive).
Rebecca:
My dogs get their crate covered with an old blanket at night but if we're out during the day we leave it uncovered.
I'd recommend just covering it at night :)
Bluebonnet:
If the dog is doing just fine in a crate, then you don't need to cover
it. If the dog is unsettled & whining or barking, cover the crate
so the dog can't see out.
Amos:
Depends on the dog, or situation. For ventilation & allowing the
dog to see OUT better, I prefer a wire crate. I can always cover it, if
needed. You cannot UNCOVER a plastic crate.
