I usually start my winter onions off in trays in the greenhouse and pop them in once they have rooted...works well for me I'm still eating last winters crop which I harvested in late spring
I've never considered growing winter onions but after the disaster this year with my summer ones, I might give it a try after seeing what you are doing. My only problem here is I'm on heavy clay and my soil tends to be wet and cold during the winter and I don't have any raised beds, though applications of compost is improving things.. However, I might set up a couple of small raised beds for winter after having seen yours. I've been mostly 'no dig' for several years, but I don't know where all the weeds have come from this year, so my fork has been very busy this week! It's been a superb day today, so I've emptied one of my compost bins as it was ready and spread the "good stuff" around. Three years ago I rebuilt my compost bins into a three-bay system using pallets and my results are much better than when I had only one large bay, and it is much easier to get at the completed compost too.
So Tony do you really mean chicken pellets that you give to chickens really, what does it do for the plants please tell me looks interesting. ❤have a great day