At the beginning of the show, the boys get out of the back seat of the Sheriff's car. Typically passengers in the back seat of a police car are allegedly criminals and therefore cannot open the back doors from the inside.
In the chicken house, Ben tells Billy that he hates chickens, and going into the houses to get eggs. However, in the first series, he had a huge chicken house in his back garden, and went in there to get fresh eggs every morning.
Correction: What Ben actually says is that he hates dealing with chickens, and that chicken coops stink. None of what he says is inconsistent with his having had chickens or a chicken house in the first series.
Correction: What Ben actually says is that he hates dealing with chickens, and that chicken coops stink. None of what he says is inconsistent with his having had chickens or a chicken house in the first series.