i used to keep bullfinches along with goldfinch greenfinch linnet redpoll sisken all in a very large avery ,not once did the bullys offer to sit a clutch ,stunning birds legal to keep ,to buy or sell they have to be closed rung , you can [to the best of my knowledge keep them unrung ,ie you have breed them yourself and left it to late to close ring them ], at least thats what was the law when i had them , also crossed various british birds with cannaries , they make cracking singers ,great hobby and try to keep them as natural as poss ,like giving them seasonal wild seeds ,meadow sweet ,thistle,even hawthorn buds was a favorite , let us no how you get on ,arron.