I’m looking for a book I read as a child (mid-1980s) about a pony named Morgan and her mother. I think it was a relatively new book at the time – the illustrations were very ’80s style and the horses had pretty big doe eyes. Definitely a book marketed to young girl.
This sounds like one of Stephen Cosgrove’s Serendipity series. Each book featured lush colorful illustrations of big-eyed animals and had a simple moral for kids, about not being snobbish, being kind to those who look different, etc. There were several books featuring a grey unicorn named Morgan: Morgan and me, Morgan and Yew, Morgan Morning, Misty Morgan, and other books, like Nitter Pitter, that featured ponies. You can see many of the cover illustrations here: http://quinceandquire.typepad.com/quince_and_quire/2009/04/vintage-books.html
This could be one of the Morgan books in the Serendipity Series by Stephen Cosgrove. The description of the horse’s eyes is what made me think of it. Copies should be available in libraries.
Morgan & Me. I had it on cassette tape too. It is in the serendipity series.