Using an agent to transport a dog from UK to US

Unless there's a reason to, they won't take your dog out of its kennel during a layover. (As far as I know, "a reason" would be if the next flight got delayed significantly, or if the dog appeared ill.) The airline staff won't risk losing your dog, or getting injured/having the dog get injured by taking it out of the kennel otherwise. (My cat flew NC -> NM which included a 2-hour layover and she was in her kennel the entire time.)

My dog didn't arrive with a leash (though I'm not sure whether my parents offered one to go with him either). The animal reception folk kindly gave me a leash, and I donated my crate to them, so it seemed a fair enough exchange. I'd imagine if you asked, they could tape a leash to the kennel, though.

The paperwork should get taped to the kennel so that it's always with the dog.

Remember that our experiences are taking a dog from the US to the UK, so whatever we tell you may not be accurate.  The US may have entirely different rules, but as Eq said, you dog will not be walked during the layover.

My friend attached a leash and collar (and a small bag of treats) to the crate and none of it made it back to me.  My dog was brought out on a slip leash (only being removed from the crate once at the ARC for inspection) and I carried her to the car.  My advice would be to keep the leash/collar with you.  Even if your dog is remove from his/her kennel for any reason, the staff will almost always use a slip leash even if you gave them a leash and collar.

She'll be stuck at the airport for 6 hours before she's allowed to get on the next flight, so I assumed they'd let her out of the kennel after being on an 8 hour flight from London. Thanks for the information, its all been helpful 

They definitely will not let them out of the kennel.  This is a major safety issue for the animal and the staff.  Imagine how frightened an animal is after an 8 hour journey on a plane.  Animals very often become aggressive due to stress and the staff they have handling them simply aren't trained to read the signals to know if its safe to remove the animal.  Needless to say, they also aren't trained to skillfully remove an animal from the kennel guaranteeing it wont get away from them.   

I've just found this website: http://www.takeyourpet.com/pages/air.htm  that suggests you can claim your dog and walk him/her yourself during the layover and then recheck them.  Not sure if thats true, but its working asking about.

Just bumping this because I just spoke with Virgin about transporting my cats from Heathrow to Boston.  I asked about needing an agent and they said that I could just book with them as always and that nothing has changed -- no agent needed.