You must identify your sheep:
Within six months of birth if they are housed overnight.
Within nine months of birth if they are not housed overnight.
Before you move them off their holding of birth if this is sooner.
Lambs intended for slaughter before they are one year old may be identified with a single electronic tag which shows only your flock number. Lambs that you intend to retain for breeding purposes or for later fattening should be tagged in the same way as older animals.
Use two identification markers on sheep over 12 months old, usually ear tags, both of which carry that animal’s unique identification number made up of the seven-digit UK number and a five-figure individual number. In most cases, one will be a yellow EID ear tag which carries an electronic chip. In Scotland it is a recommendation for it to be yellow, and in Northern Ireland the EID tag can be any colour. The other tag will be a visual identifier with the same number.
Lost or damaged ear tags must be replaced within 28 days of you discovering the loss.
Lost tags can replaced by identical tags, or a different pair of tags can be inserted, but then the new number must be cross referenced to the old ID in your flock register. Where inserting identical tags isn’t an option, and the animal is not on its holding of birth, red replacement tags must be used.
In the case of pedigree sheep, additional information may need to be printed on ear tags in order to comply with the registration rules of the relevant breed society, but this is not a legal requirement. Some societies issue their own pre-printed tags to members.