Firstly ensure that a fine, firm seedbed is prepared. Cloddy ground will harbour slugs. If growing kale, a small quantity of mustard seed mixed in can provide a valuable nurse crop for the kale, helping protect it from pigeon damage. Where oil seed rape is being grown nearby, flea beetle can prove a problem. Linseed and kale seeds can be purchased with a dressing against beetle but this must be fully incorporated in the soil as it can be toxic to birds. A useful alternative is fleece. Laid on the ground, fleece helps warm the soil faster, retains its moisture, and keeps the flea beetle off as well as other pests.
Where rabbits area a nuisance, careful crop choice can help. A triticale/linseed mix can succeed in such areas. In its early stages, the growth of triticale is prostrate so rabbits tend to overlook it. Once the air warms up, the crop growth can outpace rabbit damage. Linseed on the other hand does not seem to appeal to the rabbit palate. Sorghums, which are only suitable in the south, also seem unpalatable to grazing animals like rabbits and deer.
Heavy duty black thread strung criss-cross above the crop can help deter rooks, which otherwise will often dig up the germinating seedlings of larger seeded crops.The odd rook corpse hanging from its claw and the ubiquitous scare-crow or scare-gun are also useful.