We'll be ready to transplant some stuff outside in the next week or two. 2 years ago we built 6 raised beds. Filled them with some used duck bedding (pine straw and oak leaves), layer of clay, duck bedding, layer of compost from the garden center - not great compost. Over time, it has broken down some and we have some nice dirt, but it has settled a lot. Could use some more something this year. What is a good topper to mix in to the top layer? I saw a CL posting a couple weeks ago about horse manure. I can get cow manure what is a good option to top dress/mix in?