Dynamic cattle mobility

[Hasta]

Put the speed cap of wool-yielding cattle (sheep, goats) in reverse correlation with the amount of resource accumulated.

I.e. the more wool a sheep has - the slower it moves, down to, say, 30% speed at maximum wool storage.

This is not a vital mechanic neither would it change something drastically, but it seems like a fairly straightforward little tweak and it would be a nice touch.

Also, realism: