Hi Melanie, most things have been said, mine love Hazel, Elm, Willow, Raspberry and Brambles, Ash, but not Elder (I think it's just they don't like it, rather than not being good for them), also get tons (and I mean tons) of willowherb, thistles, last year I cut and dried nettles for them (not enough time for it this year), they are also getting the odd leaves of horseradish (I have a rogue plant in the p/tunnel), comfrey and horse chestnut.
I have stopped giving mine Hawthorn or Blackthorn, but that is more for my convenience as the cuts to my hands were getting really bad..
They also eat chickweed, dandelion and "sticky willy", again both are growing in abundance in the p/tunnel and veg garden.
The odd branch of Ivy is also welcomed, just take any flowers/berries off before feeding - very good for mid-winter treat. (My sheep got loads of it last winter, and all did very well wiht lambing etc)
Dried leaves/branches of the Prunus family are not good as they develop Prussic acid, which is toxic. OK when fed fresh though (I don't have any cherry trees here). Alder not so good either, can't remember why.
Good to hear the girls are doing fine.
Anke.