@Dr Daggy lentils are high in protein and fibre and can be fed to chicken.
Cooking or sprouting lentils and adding some to their feed will only enhance your flock’s diet. Just keep the amount lentils and all other treat foods to a maximum of 10% of their overall diet.
To sprout lentils, all you have to do is soak them in water for a couple of days. Shoots sprout up pretty quickly, and chicks love to eat the shoots.
NB: don't feed them raw!!