Hi this is my first pair of Lav. I have two questions. First, is there something wrong with their feathers to look so rough or could it by the coccidia I just treated them for? Second, how do I need to breed them to darken their color (14 weeks in picture)
Well firstly i can tell you that it is very unlikely that they have cocci. You would expect to see a listlessness with drooping wings, sleeping during the day, loss in weight for age etc.
The "rough" feathering appears to be what is called squirrel feathering which can be common in lavs that are breed lav to lav without splitting back to black. The good news is you would improve both feather quality and lavender color by adding a black to the lav. You would then be able to breed the black/lav babies to get a better quality. The birds are also at that teenage age where they can look a bit scruffy before they get their adult plumage.
Looking up close though the feathers are very squirreled. Good luck.