Consider him lucky as the menstruation of a chicken isn't really meant for human consumption. Either is the secretion from a lactating cow or other animal besides human. Processed/packaged food may seem convenient but are detrimental towards health, especially for a growing child.
The best thing to do is offer your child healthy fresh fruits, veggies, beans, legumes, nuts, seeds, etc. One person suggested the book Vegan Lunch Box, that's an idea. Really any vegan cookbook will do. I strongly suggest staying away from flour and sugar products too. They cause congestion and bloating and allergies (flour) and they also weaken the immune system, sugar is sooooooo unhealthy. You're lucky you found out now, he's not quite 2 years old, his taste buds are developing, you are creating his present AND future health by what you feed him to grow and properly develop.
Did you know that President Clinton is now on a 99.99% plant based diet? If the past President of the United States, a Rhodes Scholar figured out that's the healthiest diet, certainly us regular folk can too?
If you'd like some specific cookbooks, I've got tons, let me know.