As far as making treats go, these could not be any easier.
The starting point is a pack of boneless Chicken thigh Fillets.
Place on a tray and pop in a medium oven. The idea is to cook them not too hot, but for perhaps longer than you would do for yourself. You are aiming for chewy and a little dry, not soft and tender !
Once done they will have no pink bits inside and will be a little tough. For ease leave to cool and then cut into cubes or chunks.
Once chopped, If they are a little greasy you can always pop them back in the oven on a low heat to dry them out. Then all that is required is to put them into reasonable sized food bag portions. We normally have enough in a bag for 2 – 3 days and freeze the rest in similar sized bags. As we get to 1 day left in the current bag ( kept in the fridge) we get another bag from the freezer and put that in the fridge, allowing it to defrost overnight.