Timothy or Alfalfa pellets?

So I have a bun that I found a stray so obviously I dont know its age. Its quite small still (maybe a foot long) so im assuming its still young. I'm feeding it some rabbit food I picked up at the store when I first found my bun, but I really want to switch it over to something better. Even though I dont know its age, should I get Timothy pellets or should I get Alfalfa? Im feeding Timothy hay at the moment, so would it be ok to also feed Timothy pellets?

You can try to look up its breed to try and identify how big he is. Otherwise if you're still unsure you can try young rabbit food, alfalfa in it since it contains calcium for growing. Otherwise it his urine seems milky than you should stick to Timothy hay since the calcium creates a bad combo for their bladder/urinary system.

If you can post a couple of pictures of the rabbit next to other objects it would give us an idea of his size. Do you also have a way of weighing him? If he's a recognizable breed we might be able to give you an age estimate.

ok so i have a tiny kitchen scale and any movement causes the numbers to go up and down, but the numbers seem to hover around 1100grams or 2.4lbs (I hope this is accurate....let me know if this doesnt seem like a plausible weight). Ive also attached a pic of the bunny next to a 16.9fl oz water bottle for size. Also dont mind the wire flooring, I plan on buying a piece of wood to stick on top instead once I get my bun pottytrained.

EDIT: added more pics of the bunny so u can see what he/she looks like

Timothy pellets even if he is still a youngin most of his growings done. Lops arent big breeds.

Ok!! I'll add more to this post once I get a chance to weigh him/her again! For now how much should I feed him/her every day do you think? Also since I found bun one week ago and its been eating the bad pellets I bought with no problem, how long should i slowly incorporate new pellets into the diet if its been eating its current ones for only a week now? Also please feel free to make guesstimates on how old you think he/she is; it would be a HUGE help!

1/4 cup of pellets per 5lbs of body weight is the general consensus.
Can be slowly introduced over about a week or so.

It looks kind of like a French Lop, or a mixture of one. If so, I'm guessing it's still young...maybe 5-6 months? You might double check the weight. You can feed the Timothy pellets but a young rabbit will need more than 1/4 cup of pellets. A 6 month old French would be 5+ lbs.