Raw or extruded peas (Pisum sativum, pink-flowered cv. Milwa) were used. Extrusion reduced the trypsin inhibitor activity (TIA) from 2.35 to 0.35 mg · g^–1, but did not affect tannins content, which was about 1 g · kg^–1. A growth trial was conducted on 200 Ross 308 female broilers from day 1 to 35 of age. There were 3 treatment groups from day 1 to 14 including control without peas, 10% raw (RP) and extruded (EP) pea. From day 15 birds were kept individually, in groups of 18, and fed diets containing 15%, 20%, 25%, or 30% RP and EP. Chickens fed EP ate more feed (P ≤ 0.05) but had similar body weight gains and worse feed conversion ratio (P ≤ 0.05) than chickens fed RP. The apparent ileal digestibility (AID) of dry matter was lower in chickens fed EP than RP (P ≤ 0.01), whereas AID of protein did not differ. The AID of starch was 0.835 in the control group, in chickens fed both RP and EP it was, on average, 2 percentage points higher (P ≤ 0.01). In birds fed RP the short-chain fatty acid concentration in ileal digesta was lower (P ≤ 0.05) whereas in caecal digesta higher (P ≤ 0.01) than in birds fed EP. The dietary treatments had no effect on jejunal mucosa morphology. Diets containing up to 30% of peas with a relatively low tannins content and moderate TIA value, can be fed from the third week of life as a partial substitute of soyabean meal in broiler diets. The effects of pea extrusion on ileal nutrient digestibility and activity of gut microbiota was too small to affect performance.