Little eskimo, I wouldnt take round rubbish hay, take round some nice stuff, bag opened but full, showing you have tried it. That way, if their bun likes it, their owners have a new type of hay to enrich his life with
It also gives you a good starting point to get onto general care. You can talk about the hay which leads you on to moan about your rabbits: 'They are SO fussy, it really does worry me, especially, you know, as rabbits get those terrible dental problems when they dont eat enough' *smile and roll eyes* 'its like getting a child to eat its vegetables isnt it, they never eat enough of the stuff thats good for them, they just want the sweets, which I guess for rabbits is their rabbit pellets' *little laugh/giggle* 'I had to reduce the amount of rabbit food I was feeding to get mine to eat enough hay. Yours is so gorgeous though, I bet she's not a pickle like mine! So I thought I'd see if your bun appreciates nice hay, is she quite good at eating it?' Then they'll talk about their bun for a bit, with some prompts from you. By this point, you have not only given them advice on diet in case they didnt know (not saying that they dont, but lets face it, most people dont) in a way that doesnt look like giving advice, you have also gotten them into conversation and got them to talk about the bun, so you can pick up bits of info from that. Ask how long they've had her etc, be interested, ask open questions so they are properly talking to you, not just answering your questions. I would then, after some natural conversation, go on to ask: 'hmm I dont suppose you know anywhere local that does decent rabbit runs do you? I'm thinking of upgrading one of mine, I have one which is only *insert size of your smallest run, if you have a smallish one* but they need so much space dont they.' This suggests that rabbits need a lot of space without actually judging them, and you can also maybe slot in a question about what they have
if they mention it.
Best thing to do is be friendly, not too pushy, dont come across as preachy, as then you will make a new friend, and can ask about their bun when you see them outside etc, and slowly drop hints over time about rabbit care, invite them to see your buns etc.