Squash/pumpkin in manure bin?

Nope, it's still too fresh. Horse manure needs a very minimum of 6 months to break down; even then, I wouldn't use it myself but would wait a few more months.

Fresh could be used as the 'base' for a hotbed for the heat, but not as an actual growing medium, not until its older and lost all its smell and potency.

Hi, i grew my courgettes in the top of my pallet compost bin last year, it was filled in mid November with very fresh horse manure and i planted them out in it in mid April with fleece over the top to start with. The plants loved it, but the only drawbacks i found were the manure will rot away to about a quarter of the original height by late summer, leaving the plantsright at the bottom and also you cant use any of that lovely compost or add to it until the autumn when the plants have finished.