They couldn't turn right after leaving the front door, because there was a wall there. There was also a walled pathway which they would have to follow. It looks to me as if they were following the lingering smell of food coming from the restaurant. However I am most probably wrong.
IIRC They showed interest in some food in refuse bags and then an apartment that had rotten food in the fridge.
When the children were taken out of the front door, would that not be a route to the crèche or Main reception?
And was it possible that Gerry and Kate's scent was also on that blanket?
I think the dogs took that route because the scent of whatever it was that interested them was still there.
It is a relatively sheltered route with little reason for many members of the general public to take it and thus contaminate with their scent ... it is perfectly possible that the last people to use the route followed could have been the McCann family.
When they went out into the street there was more potential for the scent to be dissipated by the breeze as it was less sheltered it was also subject to more passing foot traffic and therefore soon lost.
Taking the training of the dogs into account, or rather the lack of it ... I think although possible it is highly improbable that they followed Madeleine's unique scent.
