Although rodenticides can be bought in various stores throughout the UK, the chemicals used are at low doses and often have little to no effect on the rodents that are being treated. When using rodenticides, they need to be closely monitored to ensure enough is taken to ensure the lethal dose is taken.
These baits should not be left in the open for non target species to have access to and should be in suitable containers. We advice it is best to avoid using these treatments yourself and to call out a professional to administer rodenticides. The UK is experiencing resistance in Rats to certain active ingredients, many are the ones found on shop shelves.
These active ingredients have been found in wild animals and birds and this is due to them being second generation poisons. This means that if the animal that has eaten the poison is eaten by something else, it can poison that animal too.
We as professionals are trained to use the correct thing in the safest way whilst taking into account the environmental impact and to minimise risk to other animals, wild and domestic as well as the general public. 

Open traps should not be left outside due to the risk or catching non-target species such as Hedgehogs and garden birds. 
All wild birds, their nests and eggs are protected by law Under the Wildlife and Countryside Act 1981