JMB - I get what you mean. We put our girls in the smaller paddock behind our property before due to lamb last year so that we could check them as much as possible. Being paranoid

, I moved them as soon as they could possibly be due and by the time the last ewe lambed the grass was micro-short and the field did have more poo on it than would normally. Meanwhile the other larger field grew like a jungle ..... oh, dear.
I think the poo built up because at the time we had no rainfall ...... remember that

. My farming neighbour said that it would be fine when I asked him about it .... as the ewes were being fed and all looked really well.
Not ideal maybe but think it's difficult juggling things on a small scale sometimes. The ewes and lambs all did really well though and I didn't scoop any of the poop.
HTH