Rat behaviour (not pets)

[Mosaic]

In the last 6 weeks I've sighted 3 rats - I've lived here for decades and never seen one. Of the three sitings, one was dead, on my back lawn. A second ran across the garden in full sunlight and did a U-trun when it saw me and the cat. The third sighting may have been the second rat again, but was running about on a neighbour's property at twilight and was found dead next day.
My question is, does this behaviour indicate rats that are acting oddly, perhaps because they've ingested poison?
I'd always thought they stayed out of sight normally.
There isn't any food being left about that I can see.
So are these daft or dying rats - or what explanations could there be?

[RATTER15]

That is quite normal behaviour for a wild rat, they frequently come out for a wander around in the daylight. It does sound like they are being poisoned if they are dying,

[Mosaic]

Thanks Ratter!

[jomifl]

Rat populations do sometimes suffer disease epidemics. I once kept quite a few pigs and had a lot of rats stealing the pigs food, then over a period of a week or so they all died. I did not use poison of any kind to control them.

[chi-chi66]

Do you live near a farm.....farmland?

[Mosaic]

I'd say we are about 300 yards from open fields....thing is we've been here decades and never seen rats moving about.
BTW I've no doubt they have always been there - it's just this coming out in full daylight malarky and rushing about not under cover.