I'm not a buyer of "new" type of things, I prefer vintage and/or antiques, but your pin designs are cute. Chicken "stuff" is fairly popular right now, so you may catch the trends.
You want to also look at other venues beside some place like Instagram - I'll be honest, that is not someplace I would even look to purchase anything, young people might.
Handmade market places like Etsy is a good option to look into and hit up the big online places like Amazon and Ebay just to see what's on the market. Etsy and pinterest are a good place to see what's trending, but remember just because people have a product listed for sale does not mean they are selling - you need to dig deeper to find out if there products are actually going out the door.
I have sold various goods online for over 12yrs - something you do need to do is research, research, research. Also just because someone is "selling" for a price (say on Ebay) that does not mean they are getting that, a lot of sellers may accept offers (all negotiated legally through Ebay). But you need to know just because someone sold a product for say $10.00 they didn't get $10.00 to stick in their pocket.
Just about all venues have a listing fee and a fee at the end when you sell (final value fee that includes a % of the TOTAL amount = selling price + shipping), you need to figure sales tax and if you accept payment through something like PayPal there is a % fee again on the TOTAL of the sale (selling price+shipping).