It's always a risk bringing in so many young players, but a lot of this bad spell is down to Sherwood IMO.
The Leicester game springs to mind straight away. Taking off your most influential players early and then losing the game is very poor management. Sherwood's been starting Agbonlahor ahead of Gestede in most games when there's no doubt Gestede looks the bigger threat and will score more goals. Westwood plays every game but he looks a player who's out of his depth in this league.
I think Villa have a really good young squad, but Sherwood isn't getting the best out of them. Richards and Lescott is a good CB partnership; that's a solid foundation then build from there with good young attacking players like Grealish, Gill, Traore and Gestede.