My take on it is that you spend time, money and a great deal of effort raising the animals to eat and for eggs. So he is abusing your generosity when he gives away the meat and eggs you gave to him for his own personal use. So, no, I don't think you're being selfish. You're not feeding the whole world for free.
This is a hard one. I totally get it in their mind they think you get the eggs for free. If it was my brother I would say pick me up x amount of feed. I'll pick the feed up when I drop your eggs off! That way he learns they aren't free.
As for your friend that helps you. This time I would give the broiler. You said you would give some for the help their were no stipulations when you told him you would give it to him. Now that you know next time you can say for your personal use. People are so removed from where food comes from. The labor and cost to care and feed etc. it's like they think animals feed their self packs it's bags, takes it's feather coat off and jumps into packaging. They have no clue.
Make sure to tell your brother you need three bags of feed one for your neighbor and one for some friends.
